Change OS X Terminal themes to saner defaults

Set the OS X Terminal themes to have more reasonable defaults and
ensure consistency across the themes so they have a predictable
starting point for personal customization.

Notable settings:

- Font: Menlo 11 pt
- Block cursor, not blinking
- No transparency or blur
- Close the window when shell exits
- Use option as meta key
- Audible bell, no visual bell
Merge pull request #229 from jbrudvik/master

Change OS X Terminal themes to saner defaults