Tidied up event handlers.

Moved switching canvas routines to pcbnew, as they are used only there right now (otherwise libgal would have to be linked to every Kicad application).

Added missing callback function (combine callback).

Removed DRAW_MODE_NORMAL, DRAW_MODE_PREPARE_EDGES, DRAW_MODE_DRAW_EDGES modes.

Fixed layer picker for exporting to pcbnew
Realigned pcb layer name with class BOARD

Dynamic contrast for netname and pin numbers ('halo' text)
Handle netname drawing even on diagonal tracks

More layer classification cleanup

Modified CMakeLists.txt in order to compile Kicad with KICAD_GAL=ON for Windows

Added settings that allow to use M cross environment (http://mxe.cc) to crosscompile Kicad for Windows.