Ensured MonoGame compatibility for Windows 8 Store Apps.
The security is such that you cannot load from a stream in the 'normal .net way' - you must instead use specific Windows.Storage methods.
Merge pull request #70 from RandolphBurt/MonoGameWin8

Ensured MonoGame compatibility for Windows 8 Store Apps.
Merge branch 'master' into monogame
Added IOS 'Define Symbol' to xamarin project