Added several functions, including email-graders and sorting/assigning
functions, and draft of design.
  config.rkd, design, grading.rkt, tutors.txt
* Add tests
  grading.rkt
* Finished send-assignments-to-graders function; untested
  grading.rkt
* Tinkering with headers to get email just right
  grading.rkt
* Added smtp config options
  config.rktd
* Added TODO
  TODO
* All tests passing
  grading.rkt
* Oops -- rebase
  config.rktd
* Added outline of grade parsing, checking, and posting functions.
  grading.rkt
* Fixed some issues with tar files and the root server directory.
Added some clean up code.
  grading.rkt
* Added function stubs for parsing returned grades
  grading.rkt
* Fixed bad headers and added ability to send body with attachment
  grading.rkt
* Added message-body parameter, and added default config file
  config.rktd
* Added .gitignore
* Remove export of testing function
  grading.rkt
* Working on IMAP graded assignment parsing
  grading.rkt, config.rktd.default
* Restructured into a package
* Added README.md
* Added config interface
  cs2500-grading/config.rkt
* Added gradebook functions
  cs2500-grading/gradebook.rkt
* Refactored some things
  cs2500-grading/graders.rkt, cs2500-grading/gradebook.rkt,
  cs2500-grading/problem-set.rkt, cs2500-grading/students.rkt,
  cs2500-grading/grading.rkt
* Remove IMAP stuff. That's a bad way to parse graded assignments
  config.rktd.default, cs2500-grading/grading.rkt
* Moved tutors.txt to roster.rkt
* Added graders.rkt
* Renamed some files to be consistent
* Forgot I didn't want to use a roster, I wanted to use users.rktd from
  the server.
  cs2500-grading/config.rkt, cs2500-grading/gradebook.rkt
* Changed problem set directory to tar "grading", where things get
  unpacked to.
  cs2500-grading/grading.rkt
* Added problem set generator, writers, etc.
  cs2500-grading/config.rkt, cs2500-grading/problem-set.rkt
* Added script and crontab to update active/inactive problem-sets
  refresh.rkt, problem-set-crontab
* Fixed bugs and added some tests to problem-set library
  cs2500-grading/problem-set.rkt
* Added list of problem-sets.
  problem-sets.rktd
Merge branch 'master' of wjb:~/git/cs2500-grading
* Added send problem sets to graders
  refresh.rkt
* Added interface to get problem-sets and filter active problem sets
  cs2500-grading/problem-set.rkt
* Fixed some mis-matched definitions/provides
  cs2500-grading/problem-set.rkt, cs2500-grading/students.rkt