Merge all these versions

[sibelius]

Can we join forces and merge all these versions of this component?

@johanneslumpe - https://github.com/johanneslumpe/react-native-selectablesectionlistview
@sunnylqm - https://github.com/sunnylqm/react-native-alphabetlistview
@dalhorinek - https://github.com/dalhorinek/react-native-letterlistview
@brentvatne - https://github.com/brentvatne/fixed-height-windowed-list-view-experiment - I think this implementation is the most efficient for now

[sunnylqm]

I am open to all forms of cooperation, especially acquisition from FB.
😆