Use the process handle returned by CreateProcessAsUserA to wait on the
process. This results in faster response times and less polling.
For example, it now restarts instantly when UAC is activated.
This also removes the call to OpenProcess and rendering the mutex unnecessary.
As a bonus, it should fix#298.
Experimental, use at your own peril!
This commit adds the ability for the LG host to install and launch with
Windows as a system service.
To install simply run `looking-glass-host.exe InstallService` or
conversely to uninstall `looking-glass-host.exe UninstallService`.
