Usage of Monday vs. M vs. Mon

**[Original report](https://bitbucket.org/laborstudents/cas-flask/issue/299) by Scott Heggen (Bitbucket: [sheggen](https://bitbucket.org/sheggen), GitHub: [sheggen](https://github.com/sheggen)).**

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We have inconsistent usage of the days field, and our mapping is not complete everywhere. It is now causing issues on the front page of CAS, where the graphs aren't displaying.

## Files affected:
- config.yaml
- timeline.js
- courseTimeline.py
- databaseInterface.py (function getCourseTimelineSchedules)

## Database tables affected:
- ScheduleDays

Start by comparing the day-name mappings in config.yaml, timeline.js, courseTimeline.py, and databaseInterface.py, especially getCourseTimelineSchedules, then inspect the ScheduleDays table values. Trace the front-page timeline data flow and confirm that all supported day forms map consistently and the graphs display again.

Written by the indexing model from the issue text.