added todo and virtual function in tracker base class
add kbd shortcut for quitting the software

Signed-off-by: Stanislaw Halik <sthalik@misaki.pl>
needless fun with main for layout

Signed-off-by: Stanislaw Halik <sthalik@misaki.pl>
Merge branch 'master' of https://github.com/opentrack/opentrack into feature/tracker_hotkeys

Conflicts:
	TODO.txt
Merge branch 'feature/libovr-0.2.5' of https://github.com/opentrack/opentrack into feature/tracker_hotkeys
fixed Rift tracker for libovr SDK 0.2.5
stupid git being a pain, I don't want this change to appear in lib-ovr branch