In-cage module mode integration

[celefthe]

Add ability to run visiomode as an in-cage module for free-access engagement. This will facilitate integration with the Habitat.

We assume that one animal will engage with Visiomode at a time, but it will have to be identified (e.g. by RFID) and its training history retrieved so that Visiomode can run the appropriate task. This requires #106 to be closed before commencing work here.