images are compared by content in case of sk/nrsr
formal adjustments towards PEP8
authorization interface changes in client module
added unit tests
structure of a change entry added to schema
entity deletion deletes related mirrored files
Merge branch 'master' of https://github.com/KohoVolit/visegrad-parliament-api

Conflicts:
	client/vpapi.py
	domain.py
	run.py