Add basic .gitignore for compiled source and project files
Clean up hard tabs, trailing whitespace, and a couple long headers
Minor cleanup and project update
Add radio settings header for better portability

Apart from concentrating all radio-related settings to a file, a header
will make it easy to share settings among projects, if necessary, by
modifying the project's header include path.
Attempt at ensuring XBee is properly handled before exiting
Remove debug print of data_out from test_radio()
Force user to request a variable number of test packets
Add script to automatically run the test suite
Get rid of unnecessary includes
Remove generated makefiles from project, updating .gitignore