Removed custom post-build commands. They will be replaced with MSBuild
Removed automatic nuGet restored on build as it's not supported by MonoDevelop

See: http://stackoverflow.com/questions/19072529/nuget-on-monodevelop-xamarin-studio
Replaced $(SolutionDir) with $(ProjectDir) in post-build events

because $(SolutionDir) is not correctly handled by XamarinStudio, see
https://bugzilla.xamarin.com/show_bug.cgi?id=15963
Corrected app config to reflect changed directory structure