Removed selection disambiguation in case when there is a choice between a footprint and a smaller component (smaller components have priority).

Smarter selection algorithm (does not allow to select both whole MODULE and its parts at the same time).
Cancel event works better (selection box does not appear after cancelling the selection tool).
Removed blinking selection box effect.
Model is accessed in more appropriate way (getModel() method).

Changed reaction of SELECTION_TOOL to ToolCancel event (first event clears selection, second one deactivates the tool).

pcbnew: hooked Tool Framework into the edit panel. Added a sample selection tool (not fully functional).