* Old control state handling code completely removed in all applications.
* Factor common control state handlers into EDA_DRAW_FRAME.
* Replaced EDA_ITEM test for newness with IsNew() method.
* Factor vertical right toolbar command handlers out of giant edit command
switch statement in EESchema and PCBNew.
Added: in file dialog, multiple file selection.
Added: Draw mode selector (in left toolbar):
Raw mode:
a Gerber image is drawn on screen without buffering.
Artifacts happen if there are negative items drawn, if more than one Gerber file is shown.
Stacked mode:
each Geber image is drawn in a buffer and after drawn on screen
No artifact with negative items.
Each Gerber image covers previous images.
OR mode (transparency mode):
each Geber image is drawn in a buffer and after drawn on screen
No artifact with negative items.
Each Gerber image is "ORed" with previous images, like in Pcbnew.
Try to optimize Draw function in buffered modes.
(Useful for PC that have problems with "blit" graphic function)
Fix minor issues.