Change casing of $_GET keys to improve compatibility with VS14

This is necessary because Visual Studio 14 makes requests such as:
    GET /FindPackagesById()?Id='System.ObjectModel' HTTP/1.1

Rather than the expected:
    GET /FindPackagesById()?id='System.ObjectModel' HTTP/1.1

Before: http://puu.sh/dkaRB/2618631e63.png
After: http://puu.sh/dkaRB/2618631e63.png