Attempt to add URL reservation to ACL for a non-administrator if an HTTPListenerException is thrown during HTTPListener start.

Attempt to add URL reservation to ACL for a non-administrator if an
HTTPListenerException is thrown during HTTPListener start. This is only
relevant for Windows NT and only if the initial ErrorCode is 5. This
will prompt the user with a window to confirm the action.
Merge pull request #806 from KevinHoward/master

Attempt to add URL reservation to ACL for a non-administrator if an HTTPListenerException is thrown during HTTPListener start.