Manage Multiple Apps

This release adds the add, remove, and replace commands which make it much easier to program a Tock board with multiple apps.

Other features:

• Sort apps by binary size for the MPU.
• Auto find .bin files so you can just run tockloader add in an app directory.
• Check to see if Make has thing to build and warn the user.
• Allow arguments in a more flexible order.
• Better ignore bluetooth devices on mac when searching for a board's serial port.