Something wrong with the binding

In 5.4.0 version the test passed
Merge pull request #556 from maratoss/patch-1

Something wrong with the binding
Fix finding DependencyProperties declared in base classes

Conflicts:
	ReactiveUI.Platforms/Xaml/WpfDependencyObjectObservableForProperty.cs
Fix this for WinRT too, in a more nightmarish way

Conflicts:
	ReactiveUI.Platforms/Xaml/DependencyObjectObservableForProperty.cs
Backport to RxUI5
Bump MonoMac Rx version to current version
Version bump to 5.5.1
Deal with null reference exception in actuallyGet methods

Iterating down through current.BaseType doesn't catch the case where
there is no BaseType causing WinRT apps to blow up unilaterally when
binding.
Merge pull request #619 from recumbent/acctuallyGet-actually-throws-on-WinRT

Actually get actually throws on WinRT should fix #563
Merge branch 'master' into rxui6-master

Conflicts:
	CommonAssemblyInfo.cs
	NuGet/ReactiveUI-Core/ReactiveUI-Core.nuspec
	NuGet/ReactiveUI-Events/ReactiveUI-Events.nuspec
	NuGet/ReactiveUI-Mobile/ReactiveUI-Mobile.nuspec
	NuGet/ReactiveUI-NLog/ReactiveUI-NLog.nuspec
	NuGet/ReactiveUI-Platforms/ReactiveUI-Platforms.nuspec
	NuGet/ReactiveUI-Testing/ReactiveUI-Testing.nuspec
	NuGet/ReactiveUI-Winforms/ReactiveUI-Winforms.nuspec
	NuGet/ReactiveUI/ReactiveUI-Xaml.nuspec
	NuGet/ReactiveUI/ReactiveUI.nuspec
	ReactiveUI.Platforms/Gtk/Properties/AssemblyInfo.cs
	ReactiveUI.Testing/ReactiveUI.Testing_MonoMac.csproj
	ReactiveUI/ReactiveUI_MonoMac.csproj
	ReactiveUI/Xaml/DependencyObjectObservableForProperty.cs
	ReactiveUI/Xaml/WpfDependencyObjectObservableForProperty.cs