Pushing the base code for platform-manager based on http://www.int6.org/development/monogame/easy-multi-platform-managment-with-monogame/
Updated the copyright text.
Added platforms; windows, metro, wp7, wp8, linux, macos, ios, android.
Only windows is tested.
Fixed XNA & GL projects.
Updated namespaces.
Updated build script names.
Merge pull request #82 from raistlinthewiz/feature/platform-manager

Feature/platform manager