Allows to try administrator mode in case of UAC control

Hi, I have made a little improvement to allow Notepad2 run in administrator mode to bypass the UAC control (which makes the file read-only).

First, Notepad2 will try to create a temp file (named like "F9168C5E-CEB2-4FAA-B6BF-329BF39FA1E4") in the target folder. If this is not successful, it will ask for UAC permissions and try again. If it fails again, Notepad2 still opens it, but as read-only.

PS: The rpcrt4.lib required below is for UUID generating.

Hope you like it :)