Hottweak - No more stuttering with Oculus Rift, let users play when Steam is offline and some new tweaks

Hi guys,

we started coding this as an hotfix but we ended up including some new features and tweaks.. lol

Let's start from fixed bugs: :gun_pistol:
- black screen when starting a mission if Steam is offline;
- random stuttering (specially on main menu map) with Oculus Rift.

New features/tweaks: :drill_picklock:
- setting "assisted clip grip" option in options menu will prevent from grabbing a magazine from ammo pouches if it's not compatible with the weapon player is holding;
- disallow the ability to put empty magazines back in ammo pouches;
- added an option to ignore secondary grip influence (useful for gun-stock weapon users).
- options menu rearrangement to make room for future options (stay tuned!)

Thanks again for supporting us!!!
Cheers!