Crime data validation

[RedMike]

There is currently no real validation in crime data authoring, but there are a number of potential problems that should be validated against.

• The known bug in the real game data with the Ultimate Plot, which is that there is a minimum score required to be assigned to events so that the crime is considered to have not been prevented; too low a score, and even doing nothing still gives the 'well done, you prevented X' ending which means the plot repeats
• Event (message/package/meeting) handling/ordering is complicated and hard to work with and can easily lead to events that don't take effect for no clear reason
• Some participants are required to exist in the plot or else things break (mastermind at a minimum, but also an organiser)

Ties in to #11 because some of the logic needs to be figured out in order to add validation for it.