Fix footprint library file extension bug in CvPcb and Pcbnew due to s-expression changes, fixes lp:1064593.

which was having difficulty with embedded nuls in files coming from PCAD.

*) Make dsnlexer.cpp's isSpace() treat nuls as whitespace.

* Add footprint methods to PCB_IO.
* Add FP_CACHE and FP_CACHE_ITEM for handling new footprint library design.
* Add code to save legacy libraries in new format.
* Change behavior of BOARD_ITEM::GetLayerName() to return the default layer
  name when the item does not have a BOARD as a parent.
* Minor changes to the module output formatter when writing to module library
  files (no BOARD as parent).
* Add new (and some that I forgot along the way) CMake flags to
  EDA_BASE_FRAME::CopyVersionInfoToClipboard().
* Add -Wno-narrowing to GCC flags to stop GCC 4.7 from complaining about
  a conversion from int to unsigned in the Boost polygon library.
* Add INPUT_STREAM_READER to richio.cpp to allow using any object derived
  from wxInputStream as a LINE_READER (needs to be validated).

(the option with the smallest number of digits for coordinates created unacceptable truncation coordinates in Excellon drill files)

Pcbnew: drill files creation: better dialog to create driil files, map files and report file. Code cleaning

Pcbnew: fix an issue when collecting vias (for instance when left clicking on a via, it was not always detected)
This bug was mainly noticeable when using buried vias (some were never detected)
Minor other fixes (typos, strings hard to translate ...)

Pcbnew: fix  compil warning and a minor bug in plot negative (frame fer plotted in white therefore not visible).
minor code cleaning

only for Pcbnew in Decimils version. These definitions are provided, but not yet used in code.

Pcbnew, plot functions: fix bug in SVG plotter, fix a minor other bug when using PS plotter (trcak width fine adjust not working)
and plot code cleaning continued

All: remove macros  MAX, MIN, ABS from macros.h and replace these macros by std::max, std::min and std::abs (mainly found in old code).

switch all <math.h> includes to <cmath> includes on an attempt to dodge some abiguous references to atan2()

dcsvg (and therefore KicadSVGFileDC)  is now unused. Use SVG plotter only to export a board SVG file.
SVG export does not use no more wxWidgets wxDC.
In pcbnew SVG files can be created by plot menu (in B&W) or export SVG menu (B&W or Color).
Export SVG menu is more suitable to create a view of a board, and plot menu is better to create a B&W document of silkscreen layers.
(In the future, the 2 menus could be merged, because they are not very different).
Note: pcbnew plot code is cleaned, mainly in dialog files, but still needs more cleanup.