subparse course description for prerequisites

[jyn514]

Currently, descriptions look something like this:

Supervised professional experience or project with selected community organizations. For each credit hour a minimum of 45 hours of supervised work and periodic consultation with the instructor are required. May be repeated for total of no more than 6 hours of credit. Prerequisite: WGST U101; junior or senior standing; GPA of 2.0 overall, 2.5 in Women's and Gender Studies courses; a minimum of 6 hours in courses approved for the Women's and Gender Studies minor numbered 300 and above; and consent of instructor.

This is a mess. Should have the following fields for prerequisites:

• max_credits (most times you can repeat the class)
• classes (list of dept, code combos)
• standing (freshman - senior)
• GPA
• major_GPA
• instructor_consent (yes/no)
• min_major_credits (for example above, 6 hours)