Simplified GrenadeSelect. Fix #604 and restores Ctrl-G cycling. Close #489.

I'm dialing GrenadeSelect complexity down so we can all get behind a simpler, non-issue, AGM_GrenadeSelect. Hopefully this closes #489, maybe allowing to integrate GrenadeSelect on WeaponSelect.

In this version, the vanilla cycling is never broken, so you can always Ctrl-G. This is done by using the addItemToUniform, Vest, Backpack to add back removed grenades, commands which I previously overlooked. 

Arma picks a default grenade on respawn, so #604 is also fixed.

Lost is the ability to prevent auto-cycling when the player runs out of the current grenade type, but I'm thinking on optionally checking for that with an onFire event in the future.