New conversion routines and sin/cos implementation for angles in decidegrees

* All items shapes  are converted to polygons.
* Polygons are merged layer by layer (for calculation time reasons,zones are not merged)
* for copper layers, vias and pads holes are substracted from polygons (but, for calculation time reasons,  not inside zones areas).
* the look is better, mainly when displaying the copper thickness
* solder and paste layers are now shown in 3D viewer.
* the code was seriously cleaned (but still needs to be enhanced).
* Note this is a work in progress which needs refinements.

- Removed spurious int casts (these are truncated anyway and will break
  doubles)

- Applied the Distance, GetLineLength, EuclideanNorm, DEG2RAD, RAD2DEG
  ArcTangente and NORMALIZE* functions where possible

- ArcTangente now returns double and handles the 0,0 case like atan2, so
  it's no longer necessary to check for it before calling

- Small functions in trigo moved as inline

In most case the assignment to null was not necessary since it was easily provable that the (local) variable wouldn't have referenced after that anyway.

* Tweak the NETLIST_READER code to allow for component footprint names that
  are not found in any library to generate a warning instead of an error and
  update the board accordingly.
* Don't display undo warning in netlist dialog when dry run option selected.
* Rename netlist_reader_common.cpp to netlist_reader.cpp
* Rename netlist_reader_firstformat.cpp to legacy_netlist_reader.cpp
* Rename netlist_reader_kicad.cpp to kicad_netlist_reader.cpp
* Remove cvpcb/read_write_cmpfile.cpp and move the single function it
  contained into cvframe.cpp
* Remove cvpcb/loadcmp.cpp and move the single function it contained into
  class_DisplayFootprintsFrame.cpp.
* Remove cvpcb/readschematicnetlist.cpp and move the single function it
  contained into cvframe.cpp.
* Remove cvpcb/setvisu.cpp and move the few functions it contained into
  the appropriate source file.

* Create separate NETLIST object to hold contents of netlist files.
* Read entire netlist and footprint link files before making applying
  changes to board.
* Add BOARD::ReplaceNetlist() function to eliminate the calls between the
  NETLIST_READER, PCB_EDIT_FRAME, and BOARD objects.
* Change placement of new components below the center of the current board
  or in the center of the page if the BOARD is empty.
* Add dry run option to netlist dialog to print changes to message control
  without making changes.
* Add button to netlist dialog to allow saving contents of message control
  to a file.
* Eliminate the need to compile netlist_reader_*.cpp in both CvPcb and Pcbnew.
* Add netlist_reader_*.cpp to the pcbcommon library.
* Remove redundant load component link file code from CvPcb.
* Modify CvPcb new to work with the new NETLIST_READER object.
* Add compare() function and < and == operators to FPID object.
* Add REPORTER class to hide an underlying string writing implementation for
  use in low level objects.  Thank you Dick for the idea.
* Lots of minor coding policy, Doxygen comment, and missing license fixes.

Also removed EDA_DRAW_FRAME::OnGrid which was totally dead (empty and unused)

Pcbnew: load footprint from modview: Because modview allows user to choose the footprint library, the selected library is forced when the footprint is loaded.
I am not sure this is 100% better, but this new behavior has some advantages, mainly in the footprint editor (you can load a footprint outside the selected library)

Slightly retuned for compensating the new position.

Dynamic contrast for netname and pin numbers ('halo' text)
Handle netname drawing even on diagonal tracks

More layer classification cleanup

bit string version of property_tree. The ram resident structure of the ptree is
mostly compatible with one created using the xml_parser from
boost::property_tree, with slight differences in the way atoms are stored. The
result is you can use Format() to convert from xml to s-expression, but not the
other way around. You can write a simple s-expression beautifier in just a few
lines of code.

The main value however is the s-expression parser, i.e. Scan(), which is an
alternative to crafting a custom recursive descent parser for a particular
grammar. The tipping point depends on whether you want to read only a small
portion of a much larger document. If so, then using the ptree will likely be a
"faster to code" route. Documentation on how to navigate a ptree can be found on
the boost website and there are a number of examples in the
pcbnew/eagle_plugin.cpp file in this project. Powerful path navigation support
makes it easy to extract a subset of a ptree.

(when disabled they are shown as standard holes, a lot less distracting
than the previous fixed yellow color)

Better description for entities on right click menu and panel
Typo fixes and some comment reformats

Charras beat me on fixing the include/sch_item_struct.h include issue from 4069

Gerbview, layer manager: add option (popup menu) to always keep layers not visible but the active layer, even when the active layer is changed.
Pcbnew: fix swig warning for operator EDA_COLOR_T::++  (changed to function EDA_COLOR_T:: NextColor)

the spurious warning about stuff that couldn't be seen when changing
colours.
NOTE that the 'net name' layer is present and configurable but non used 
anywhere!

All: change some texts and messages hard to translate, or not translatable (and some incorrect messages).
Pcbnew, layer manager: add option (popup menu) to always keep copper layers not visible but the active layer, even when the active layer is changed.
Usefull for multilayer ( more than 4 layers) PCBs.

In particular the new mechanism for handling extended color palettes is in place,
included renaming the ini keys and saving the color name instead of its index; this means better forward compatibility with palette changes.

Since ini keys are changed, colors will be reset

Implemented the LAYER_NUM typedef (LAYER was already taken as a class name...) to represent a layer number.

- Renamed ReturnMaskLayer to GetLayerMask (since it's a plain getter)

Fix rounding issue when a double is stored in a wxConfig file (wxWidgets 2.9.4 store only 4 digits in mantissa).
A new inline function ConfigBaseWriteDouble( config, key,  double_value )  is used instead of config->Write(  key, double_value ) which store 12 digits

pcbnew: fix print format in THROW_IO_ERROR
        fix properties file export_vrml.cpp