Return rich IAppliedBindingInfo object when using View Bindings.
Fix style.
Rename AppliedBindingInfo to ReactiveBinding
Make BindComand return an IReactiveBinding object.
Merge remote-tracking branch 'origin/rxui5-master' into IAppliedBindingInfo

Conflicts:
	ReactiveUI/PropertyBinding.cs
Single class per file is Terribad
Merge remote-tracking branch 'origin/rxui5-master' into IAppliedBindingInfo

Conflicts:
	ReactiveUI/PropertyBinding.cs
Move old ReactiveCommand to a Legacy folder
There is Only One ReactiveCommand
Port the command mixins over
Fix the build
This class is dumb
Get the ReactiveCommand tests in shape
Get the tests passing
Add Changed observable to expose binding changes on IReactiveBinding.
Returning null seems like a reasonable solution.
Add tests for AllowConcurrentExecution
DistinctUntilChanged + First = kablooey
Merge pull request #288 from reactiveui/rewrite-reactiveasynccommand

Rewrite ReactiveCommand
Merge remote-tracking branch 'origin/rxui5-master' into IAppliedBindingInfo