Handle parsing ambiguous dates from Quest schedules

[mduan]

When parsing schedules from Quest, we assume date range information for courses come in MM/DD/YYYY format (which is the case for most users).

However, Quest also has schedules where the date format is DD/MM/YYYY format for a small subset of users. We will need to use heuristics to guess which format the dates are in.

Below is a link to a schedule with the unsupported DD/MM/YYYY format: https://gist.github.com/mduan/9334117.