Add method for players using character-based movement to quickly run backwards

When using "legacy" (camera-based) movement, characters can run straight backwards by pressing [S]. Similarly, gamepad users can run straight backward with no problem.

However, when using "standard" (character-based) movement, it's extremely difficult to quickly run backwards. You must first turn your character, a very slow proposition if you favor the keyboard for turning instead of the mouse.

The "standard" movement feels way more natural (to me, and likely to many others - I mean, it's STANDARD, right!?), but is currently a huge hindrance in challenging boss encounters. A "quick turn" keybind would alleviate this, allowing you to quickly turn your character and begin running forward, however all we have is [V] to flip the camera. Moving forward with the camera flipped with still just move forward (based on the character's perspective).

I like the slow backpedal, but not when backing out of an AoE telegraph. It'd be nice if there was a quick turn or is tapping [S] twice quickly put you into a full run backwards instead of a backpedal.