Move some logic about available slots out of helper methods, and onto the Invitiation/Sessions models.
Push some more logic down to Invitations, rather than checking roles from the views.
Don't produce output from these Rake tasks if running in the test suite.
Shorter version of these if clauses.
Control output of rake tasks using test doubles rather than checking the Rails environment.
Merge pull request #155 from creature/refactoring

Move some model logic out of a presenter; tidy up test output.