Html exporting - Task 7 on Trello

Most of this PR is just getting the freemarker source code into our source. I tried using a .jar to no avail. The easiest option was to simply include the source files. (We might clean this up if we can dig through and figure out what we don't need.)

The only real changes are in src/io/Exporter.java, src/io/GhostGraderIOTestFile.java and src/io/export_template.html

I interpreted the goal of this task to simply hookup our object with an html file. At the moment, the html file only displays a few simple fields from the MyCourse object. I plan on working with Tarah in the next sprint to actually design the real html file and get the details hooked up. Let me know if this was the correct interpretation or if I need to do some more detailed work on the template.