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

Removed old color and visiblity dialog
work in progress.
See also TODO, P0)

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

    * in variable names, change non existent word Hight to High
    * Remove redundant tool in left toolbar (option toolbar)
      (this option is now in layers manager)
    * Show layers in horizontal combo box in same order as in layer manager.
++all:
    minor code cleaning.

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.