Set viewValue to any everywhere

Documentation states `viewValue` and `modelValue` to be a string but other types do work and it's common to use them.
Merge pull request #1148 from santialbo/patch-1

Angular.js: Set viewValue to any everywhere
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.