Reset attack animation time every time Combat#attack is called.
Implement locomotion animation blending using state_machine.

Bugs with idle-to-walk transition persist, however.
Implement method to convert frames to seconds.
Adjust jump velocity and movement capability while in air.
Sync movement speed to animation playback rate.
Update human skeleton with run run animation.
Update mass and friction for better game feel.
Stop debug printing for combat things.