Behaviours and strange behaviours

To learn more about IIIF behaviours visit: https://iiif.io/api/presentation/3.0/#behavior

IIIFpres firstly checks that the behaviour is inside BEHAVIOURS global variable:

from IIIFpres import iiifpapi3
iiifpapi3.BEHAVIOURS

So if you want to use non-standard behaviour you have to append to this list first to bypass the check:

iiifpapi3.BEHAVIOURS.append("mystrangebehaviour")

Then checks if the behaviour is applied to the right IIIF object. At the moment it does not check if:

1. The objects referenced by Range and Collection have the right attributes e.g. Canvas must have a duration for auto-advance behaviour
2. If the behaviour disjoint with another e.g. repeat with `no-repeat