Consolidate course code processing functions

Combine ps_to_bb_course_code, ps_to_bb_course_components,
ps_to_ares_semester, and subject_and_number_from_ps_code into a single
function that returns all the information named process_ps_course_code.
Add nodeunit to dependencies

nodeunit will be used to write and run unit tests.
Fix bb_course_code in process_ps_course_code

The variable with the bb_code value is called bb_course_code.
Remove packages from source control. Packages should be installed by kanso.
Ignore packages installed by kanso
Create unit tests for lmsutils