Fixes for WP8 runtime:
-Fixes conditional compilation symbols.
-Adds all the VSIX dependencies to the VS2012Ingration solution
-Adds the  alternative runtimes to the VS2012Ingration solution
-Removes useless build configurations from WindowsStore and Windows Phone alternative runtimes
-Removes duplicates from Windows Phone alternative runtime
Merge pull request #1 from jagui/feature/win8fixes

Fixes for WP8 runtime: