Repackaged 3rd December release. Odd dll issue for Store builds.

*Note found an 8.1 bug which needs resolving with the package.
Will also refresh for a more recent release with this fix
Merge branch 'develop' of https://github.com/mono/MonoGame into NuGet_update_package
Updated for December 10 cut.
Resolved Windows 8 build issue
Windows 8.1 package updated to be fully functional
Merge pull request #2161 from DDReaper/NuGet_update_package

Nu get update package update 10th December
Merge branch 'develop' of https://github.com/mono/MonoGame into toRelease