rm 1ms sleep from main loop;
rm 1ms sleep from main loop;

It's causing massive problems on windows, and sleeping for zero ms
is good enough to relinquish CPU time to the OS.  VR APIs also do
their own sleeping.

bjornbytes/lovr,bjornbytes/lovr,bjornbytes/lovr,bjornbytes/lovr,bjornbytes/lovr