Joystick additions for menu, axis defaults, and vertical look toggle

• Menu: Map Joy 2 to menu back (escape)
• Menu: Map Joy 3 to control clear (backspace)
• Make M_Responder operate on (ev->type == ev_keydown) for joy/mouse inputs ONLY IF (menuactive) because joy/mouse buttons were triggering menu-specific keys in-game
• Change joystick axis defaults to 360-friendly values
  • Move with Left Stick; Camera with Right Stick; Ring Toss with Left Trigger; Normal Toss with Right Trigger
• Tie joystick vertical look to cv_alwaysfreelook and cv_chasefreelook (for next)
• Add joystick vertical look toggle to menu

Based on next because of M_Responder quirk fix and cv_chasefreelook