Electric bikes & muscle power [CR\WIP]

Muscle engines (pedals, hand rims) can have alternators attached. Only one muscle engine can be installed on a vehicle. This can be in combination with any number of regular engines. 

There is a max weight that a muscle engine can move, which is based on strength. Over this, the vehicle won't accelerate unless another engine is helping.

TODO:
- [x] Reduce mechanics difficulty for installing muscle engine.
- [ ] Some kind of cost for using a muscle engine. I'm thinking hunger.
- [ ] Medium storage battery for electric bikes. Small one runs out in 1 minute with small electric motor.

Old OP:
~~Sorry, no hotrods found here. This is just a refactor that makes the muscle engines (Pedals, hand rims, paddles) more generic within the code, since they all do the same thing. I was trying to add electric bikes into the game, and figured this would make it easier later.~~

CR for any other small things that could be improved in the vehicle class.~~
After the bionic rebalance, the torsion ratchet charges a point every turn.  This may need buffed to match.