Teamkilling does not behave as expected

[MuffinTastic]

Setting friendly_fire to true in the config should allow you to kill your teammates whenever you like, but it doesn't. This was caused by a change in how teamkilling configuration is handled, namely commit 93d0d48.

The previous logic for teamkilling was: off/false, only on_grief, on/true.

The current logic is: friendly_fire and teamkilling on grief now act entirely independently, with the introduction of friendly_fire_on_grief. The surrounding code was never updated to reflect that though, so when friendly_fire_on_grief is true it ends up following the code path previously meant for when friendly_fire was on_grief, and returning when you haven't griefed anything recently, even if friendly_fire is true.

#448 is a symptom of this.

My recommendation is honestly just to revert it back to the way it was. Remove friendly_fire_on_grief, add "on_grief" back as an option for friendly_fire.