Added UIStepper to LinkerPleaseInclude-file

UIStepper would sometimes be stripped from the assemblies so bindings
would fail on the Value property.
Added UIPageControl to LinkerPleaseInclude-file

UIPageControl would sometimes be stripped from the assemblies so
bindings would fail on the Pages property and the ValueChanged event.
Merge branch '3.2' of github.com:PelleRavn/MvvmCross into 3.5

Conflicts:
	nuspec/TouchContent/LinkerPleaseInclude.cs.pp