Add FSharp style observable events for common cases

Why: This is ReactiveUI we love observables and C# events
suck. There is Observable.FromEventPattern but who remembers
the correct signiture for that. Not me! I just want to do this
in my code

    control.MouseDownObservable()
      .Sample(Timespan.FromMilliseconds(500))
      .Subscribe(x=>Console.WriteLine("Yeah!"));

This is easy in F# cause events implement Observable. We want
this in C#!.

How: T4 templates of course. At the top of the template you
put in some types and the template finds the associated assemblies
and then finds all the events for those assemblies and
then generates extension methods that wrap Observable.FromEventPattern
for you.
Merge remote-tracking branch 'origin/rxui5-master' into events-as-observables
Move WPFEvents to own library
WIP
Merge branch 'rxui5-master' into events-as-observables

Conflicts:
	MakeRelease.ps1
Write an app to render events to a C# file
Rig the csproj file to build against 4.5
Rewrite EventBuilder using Mono.Cecil because WinRT
Everything except for fucking WinRT works
Fuck WinRT so hard
Update Solution file
Don't check these in
Fix up csproj files
Merge branch 'rxui5-master' into events-as-observables
Visual Studio is the worst thing
Hide generated events
I don't even know.
Version bump to 4.6.0
Upgrade some packages
Version bump to 4.6.1