Normalise whitespace.
Change start of academic year to be September.

This is a fairly arbitrary cut-off, but it does allow for tours, etc.
Begin implementing GetConcertsInPreviousSeason().

Return concerts that took place in the previous season.
Do not return concerts from the current season.

This test passes out of the box because I took too large a step in the
previous implementation.
Do not return concerts from the season before last

Again, this passes out of the box. Bother.
Return concerts from the current calendar year.

Concerts in the previous season might have taken place in the current
calendar year, so return those too. This passes out of the box as well. It
really looks like this method is a one-liner. Weird.
Merge branch 'feature/complete-concert-details-service' into develop