Follow up master/HEAD
Add a few definitions. BehaviorSubject, ReplaySubject, ConnectableObservable
Fix definition around Subject.
Merge pull request #1152 from Yukimune/rx.js.mySpike

Added BehaviorSubject, ReplaySubject, ConnectableObservable and fixed Subject declaration.
added rethinkdb
documentation
initial Collection methods
_.all/_.every
_.any/_.some
_.at
_.at test fix + _.map/_.collect definitions
_.contains/_.include definition
_.countBy definitions and tests
_.countBy documentation updates
_.find/_.detect and _.findLast definitions
_.forEach/_.each definitions
_.forEachRight/_.eachRight definitions
_.filter/_.select definitions
_.findWhere definitions
_.reduce/_.foldl/_.inject definitions
_.reduceRight/_.foldr
_.groupBy definitions
_.indexBy definitions
_.invoke definitions, removed underscore _.findWhere definition