Refactor player animations to a state machine with a command pattern

[the-simian]

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[the-simian]

this is nearly done on #36

[the-simian]

this has taken a little longer than expected, but I am happy with the results.

I think I researched every single implementation out there, and tried them all out at some point. I even tried to roll my own solution at one point, but abandoned that approach. Ultimately I decided to use machina.js for the high level tool to manage the state transitions. I intentionally made a character with 'significant' animation concerns since that is much more like what a 'real' game might be like.

I did learn, in the process, there's a lot of different behavior tree implementations, which is a good approach for enemy AI. That will be in a future update.

I plan on doing a write-up on both of these so that other people know how to use the pattern that is there.

[the-simian]

Ok this is sufficiently far along I am going to close. The pattern is in place, even though there's some stuff left (like shooting) to do.