All: fixing a recent problem when using scroll bars: the full screen was redrawn, that can be very slow in Pcbnew.

Added sample gerber files for test (gerbview has problem with 2 files)

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

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

    * 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.

patch for relative paths.

Code cleaning.
Patch for 3D problem with macOSX

files cleaning

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

Fixed aui component for other platform other than OSX, with wxwidgets 2.9 we dont need to define aui