Fix timer:stop() for Executors.callLaterTime

timer = flower.Executors.callLaterTime()
timer:stop()
-- Now timer:stop() cancel the timer.
Merge pull request #103 from alex1line/master

Fix timer:stop() for Executors.callLaterTime
Added events for middle and right mouse button press and drag
Merge pull request #104 from axboureau/master

Added events for middle and right mouse button press and drag to flower library and flower sample
Merge branch 'master' into dev