misc fixes (see description)

- levelup takes in a char to account for bad inputs
- choosing age accounts for bad inputs
- while in inventory, if user chooses out of range slot it just
reprompts instead of exiting with a vector error
- type 'Q' anywhere to quit instead of type 'q' in town/'Q' in dungeon
(makes it harder to accidentally quit since it's capital?)
- clips entered user name if too long, avoids printing user info looking
bad
- other misc changes