update README
update README
fix Mathematics.floor(), ceil(), fwrap() for neko, don't use Std.int() for cpp
Entity.findXXXById() -> findXXXByName()
Merge remote-tracking branch 'origin/dev' into dev

Conflicts:
	README.md
optional subclass check in Entity.findXXXByClass()
don't halt Timebase in MainLoop
make de.polygonal.core.time.Delay cancelable
add math.RootSolver class
update README
pass message sender to Entity.onMessage()
keep existing fields in Version macro
add Entity.is() and Entity.isAny()
update README
optional parameters and nullability: keep one style
Tween: pass min/max values to START/FINISH update
tweening: minor fixes, add example
update README
Observable: consider group id in event filtering; simplify neko support by using only 30 bits
another tween example