scrollview: start new scrollview from thomas works
scrollview: do effect for x and y now.
scrollview: better damped parameters, start to reduce the code
scrollview: implement timeout / children dispatching, same as the previous implementation. remove the old animation-based implementation
effects: introduce kivy.effects with KineticEffect, ScrollEffect, DampedScrollEffect, OpacityScrollEffect.
effects: more documentation
clock: the tick_draw _must_ be done even if the canvas doesn't need redraw.
setup: ensure kivy.effects will be installed
scrollview: fix pos/size scroll and use a trigger instead. Splitter works on kivycatalog again.