Move logic for determining whether or not a file can be submitted into its own method.
Submit all files beneath a parent directory.
Properly remove files that cannot be submitted.
Clean up the logic for determining whether or not a file is in the edu/pdx/cs410J/<userId> directory.
To address issue #65, allow files in the koans directories ("beginner", "intermediate", and "advanced") to be submitted by the Submit program.
Remove code for extracting koans submissions that were sent via an email attachment.
Update the usage information to note that a directory name can be included on the command line.
Merge pull request #93 from DavidWhitlock/issue-65-submit-koans-with-Submit

Allow koans files to be submitted with the Submit program.  

To address issue #65, I added the ability to submit all files in a directory using the Submit program and I allowed submitted files to reside in a directory names beginner, intermediate, and advanced. Along the way, I refactored a bunch of code to make it more readable and easier to extend. I also got rid of the now obsolete code for downloading koans submissions as zip files attached to emails.