Add IReactiveCommand to ReactiveCommand<T>
Fixup RxUI_XSIOS.sln, and add RxUI.Events stuff to gitignore
Merge pull request #573 from reactiveui/fixup_rxui_xsios_sln

Fixup RxUI_XSIOS.sln, and add RxUI.Events stuff to gitignore
Merge pull request #572 from reactiveui/add_ireactivecommand

Add IReactiveCommand to ReactiveCommand<T>