For embedded use, it's convenient to be able to disable the cursor
completely, without having to audit and fix up all your third-party
code (e.g. Mozilla Firefox).
Add -nocursor and -cursor server options to enable and disable the
cursor. The default is still -cursor, but embedded users can run the
server with -nocursor to hide the cursor regardless of what
application developers do.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>