Better redistribution algorithm and somewhat critical bugfix

[madsobitsoe]

• Bugfix: Students belonging to a "phony section" would be filtered out before redistribution and creating a ta_list.yml. They are now "grabbed" before the "phony sections" are deleted, and will be included in the ta_list.yml
• Algorithm: Less code, less dictionaries, less passes, (hopefully) less bugs.
• Extras: Prettier info and debug prints