Fixing vertical size of the design rules dialog to meet our minimal screen size requirement (768 pixels height)

* Changed line clipping function in gr_basic.cpp when USE_WX_ZOOM is
  enabled.
* Set wxDC clipping region to client size when drawing outside of paint
  event handler.
* Updated kicad and eeschema CMake files as the common library now
  requires linking to the polygon library.

* Corrected over zealous clipping fix in last commit.
* Tweaked clip box rectangle size.
* Fixed cross hair cursor drawing bug.

* Fixed clipping bug when USE_WX_ZOOM is enabled that causes rats nest
  to be drawn incorrectly.
* Fix ambiguous function error in trigo.cpp when building with MSVS.
* Add instructions for building wxWidgets with graphics context
  enabled (GDI+) using MinGW/MSYS to COMPILING.txt.
* Initial EESchema find dialog work.
* Set modified flag when using PCBNew global deletion dialog to prevent
  closing without warning user of changes.

* Implement code to allow wxDC to handle coordinate conversions between
  device and drawing units.
* Add build settings to enable wxGCDC for wxGraphicsContext testing.
* Remove wxAUI conditional build cruft as it is now required to build
  Kicad.
* Fix scroll increment size regression to prevent jumping around the
  zoom center position.
* Add find GDI+ cmake module for building on WXMSW when wxGraphicsContext
  is enabled.

Some fixes.

removed global variables and a lot of redundancies

hide/show rastnest in pcbnew is currently not working, will be fixed soon

Pcbnew :added option to show/hide footprints values and/or references

Better code in fast draw grid algo (drawpanel.cpp):must be faster, and minor refresh problems removed under wxGTK

fixed minor problems and fixed Layer Alignment Target bug.

* Remove redundant background redrawing RedrawActiveWindow.
* Remove redundant managed cursor callback in RedrawActiveWindow.
* Use refresh to redraw instead of directly calling RedrawActiveWindow.
* Remove unused SetDrawBgColor for drawframe.cpp.
* Fix compiler warning in cvpcb/cvframe.cpp.
* Fix menu spelling and syntax errors in pcbnew.
* Rename Trace_Curseur to DrawCursor in common/drawpanel.cpp.

Code cleaning.
Patch for 3D problem with macOSX

files cleaning

fixed a grid refresh problem when using fast algo in drawpanel.cpp

Added patch for macOSX
turn on fast algo for draw grid (should work now)

Fast algo currently disabled (tests needed)

Ugly but necessary fix to display toolbars in latest Linux version (tested with Ubuntu 9.10 updated)