Selectors

[Odonno]

Add ability to create selectors with Rx.NET in order to optimize applications and avoid repeatable code.

• [x] Memoized selectors (all selectors should be memoized)
• [x] 2 to N selector/map functions in parameters
• [x] Selectors with props parameter

Example:

Store.Select(SelectRecentlyWatchedMovies, 20)
    .Subscribe(...);