Fix fullscreen toggle shortcut

Remove the "Meta" modifier so that the shortcut works on Windows.
Different fullscreen shortcuts for Mac and Windows

Revert to the original Mac OSX key combination and provide alternative for Windows.
draw skeleton shapes at at correct positions
move code to SkeletonModel::stepRagdollForward()
Merge pull request #3050 from ctrlaltdavid/fix_fullscreen_shortcut

Fix fullscreen toggle shortcut
remove some unused var warnings in Release build
fixed perf stats on phys simulation
more complete physics iteration for stability
merge upstream/master into andrew/ragdoll