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)