Summary: Recycling and dealloc were not implemented at all before for Slider, so I've taken a first stab at it. It's a little more complex than I initially thought, due to things I don't 100% understand about UISlider as well as Fabric, so I've left a TODO note to fix this at some point. We should be aware that view recycling doesn't appear to be working the way I would expect currently though.
Reviewed By: shergin
Differential Revision: D13965475
fbshipit-source-id: fd18a219cead770b63b514fdc868e23214e735b7
3cca9e76c5