Merge pull request #432 from reactiveui/collection-interfaces

Improve interfaces for reactive collections.
Update to Rx 2.2.2
Start to retarget things to the PLib version
Rewrite Reflection to use new 4.5 API
This and That
Merge pull request #438 from reactiveui/portable-xamarin

Portable ReactiveUI.dll, even on Xamarin
Merge remote-tracking branch 'origin/master' into rxui6-master

Conflicts:
	ReactiveUI/Interfaces.cs
DeclaredMethods = ~BindingFlags.FlattenHierarchy, RuntimeMethods == BindingFlags.FlattenHierarchy
Fix up Windows build
Fix up failing tests around RegisterAsync
Merge pull request #442 from reactiveui/reflection-fixes

Reflection fixes
Use SequenceEqual in field initializer
Merge pull request #439 from dahlbyk/stringFormat

Drive-by refactoring: stringFormat
Reflection fixups.
Fixup the Rx assemblies in WP8.
Update NuSpecs to pull in Ms RX
Update binaries with the MS Rx PCL's from Profile 78
Merge pull request #446 from onovotny/Rx-binaries-current-ver

Update binaries with the MS Rx PCL's from Profile 78
Fix typo
Merge pull request #444 from onovotny/rxui6-nuget-fixes

Update NuSpecs to pull in Ms RX