BackButton support for WP8
Added fake GamePad class
Implemented Game.Exit()
Merge branch 'orientation' of https://github.com/Nezz/MonoGame into wp8_backbutton_v2
Get BackPressed from page
Merge branch 'orientation' of https://github.com/Nezz/MonoGame into wp8_backbutton_V2
Updated template
Merge branch 'orientation' of https://github.com/Nezz/MonoGame into wp8_backbutton_V2
Merge branch 'orientation' of https://github.com/Nezz/MonoGame into wp8_backbutton_V2
Added MaxTextureSize to GraphicsDevice

In XNA Textures can be larger than the screen (though there is a
maximum size) while in OpenGL they can't. This property returns the max
allowed. (for Windows DirectX it uses the XNA values to help porting)
Revert "Added MaxTextureSize to GraphicsDevice"

This reverts commit 1d064c458491815b2d9b868c13e07df1e35ec425.
Merge remote-tracking branch 'upstream/develop' into develop
[MonoMac] SaveAs* Implementations for MonoMac
Added info for the source versions of assimp/assimp-net binaries.
Minimal importer. Geometry doesn't look quite right yet.
Filled in missing content type methods.
ModelMeshPart.Effect now removes the old effect from the ModelMesh if no one else is using it.
Fixed mouse scroll wheel on WinDX desktop.
FindImporterByExtension() is no longer case sensitive.
Merge branch 'develop3d' of https://github.com/mono/MonoGame into wp8_backbutton_V2
Allowing texture name in sampler states using parenthesis.
Fixed case where a disposed texture is still in the TextureCollection.