Default control changes for 2.1.21

The team wanted to address the game's control difficulties, and 2.1.21 seemed like a good time to start the new defaults in prep for 2.2.

The decision is already made to go this direction; I'm just throwing this up here to make sure the implementation is correct.

• Movement defaults to WASD; Camera defaults to Mouse and Arrow Keys
• Mouse sensitivity is adjusted from an absurdly high '34' to a more reasonable '20'.
  • Thoughts: I thought 19 was just a bit short; 18- was too tank-like, and 21+ was too slippery. I could use some feedback on this.
• Vertical mouselook toggle is split between First-Person and Third-Person settings. It's enabled by default in first person, and disabled by default in third person.
• Pause is remapped to 'P' by default, while the Pause/Break key is permanently hardcoded to the pause function. You'll see why, later
• The control menu is changed to group together movement and camera controls, to show the inherent connection between the two.