DepthStencilState not setting the ReferenceStencil value

DepthStencilState was not setting ReferenceStencil which causes strange
results when using stencil masks with ReferenceStencil other than zero.
It now looks ok (similar to XNA) for my stencil shadow implementation.
Merge remote-tracking branch 'upstream/develop3d' into nkastBranch
Merge pull request #1173 from nkast/nkastBranch

DepthStencilState was not setting ReferenceStencil
Added a clean target and the content processor target to the build script
Updated the installer to include the new pages
Remvoed Xamarin page from the installer
MonoGame 3.0 Release 2013-01-11
Fixed Installer to run OpenAL silently.
Fixed the Linux and Windows Templates to link to SDL and SDL_mixer.dll (for linux)
Fixed some of the registry entries for the installer
added SDL_mixer.dll
Provided additional information in (re)thrown exceptions.
Merge pull request #1177 from Qbit86/develop3d

Provided additional information in (re)thrown exceptions.
Merge branch 'develop3d' of https://github.com/mono/MonoGame into develop3d