Fix WindowsGL project template : use the right Program Files folder and ...

...fix an issue with the resolving of assembly references finding the WindowsPhone ones before the Windows ones (error was MessageFilterHook type not found when launching a new WindowsGL project).

Commit message is self-explanatory. I was not able to compile and run a newly created Windows GL project using Windows build #280 from the Jenkins build server. These fixes solve the issues I had.