Improve scheduler to optimize room allocation

[ianbjacobs]

We often find ourselves manually moving meetings around to improve a schedule. Some of the things we look for:

• Can a switch be avoided by swapping two meetings in the same slot (where the swap would not create a new switch conflict)?
• Where two rooms are used, is it possible to free up one of the rooms by putting all the sessions in a single room (without creating conflicts such as capacity issues)?

Perhaps the scheduler could do some of this work because it seems deterministic.