Merge pull request #1 from mono/develop

Update my personal fork to the latest version of MonoGame.
Fix for ResolveRelativePath stripping drive char

As per issues #3064 and #3041, parsing a file path through the
ResolveRelativePath function was stripping out the drive letter. This
crash was especially prominent for the sound and video loaders.

This fix will strip out the platform-specific path separation character
if it exists and will not try to remove it if it doesn't.
Update Icon and Preview Image for Windows Phone 8.1 Template
Update Project Name for wp8.1
Merge branch 'develop' of github.com:mono/MonoGame into develop
Add Universal Template for MonoGame
Update GamePage.xaml on Universal Template
Update Readme with wp 8.1 support
Add correct MonoGame references and remove unused variable from wp8.1 and universal template
Fix identation
Fix identation
Merge branch 'develop' of https://github.com/lordoaty/MonoGame into relpath
Refactor of ResolveRelativePath() to support nix systems.
Fixed incorrect `notSeparator` on Windows systems.
Generate cleanup and comments.
Added FileHelpers.ForwardSlash and BackwardSlash to makestuff clearer.
Added unit test for FileHelpers.ResolveRelativePath().
Clearer double backslash.
Simplified the test parameters.
Formatted the test cases better.
Added more test cases.
Added double forward slash case.
Merge branch 'testsfix' into relpath
Fix autorotate behavior during launch on iOS
Remove GC.Collect() when receiving memory warnings