First version of tetris example
Implementation of F6 (reset view), still incorrect
Merge branch 'master' into wip

Conflicts:
	src/Flowskell/Viewer.hs
Do a screenshot (F7), store source filepath in state and not in environment
Color command can now be used to set alpha transparency
Rename example
Fix syntax error
Fix shader example
Update TODO
F3 displays FPS
tetris wip
repl test