a few attachments tests added
added check that parent has no attachments before adding any
Merge branch 'develop' into attachments-tests

Conflicts:
	src/ralph_assets/tests/utils/sam.py
license's assets autocompleted by device.hostname & new file for lookups test
flake ready
Merge pull request #393 from xliiv/license-lookup

License lookup
postreview fixes + rm duplicated ACLInheritanceTest
Merge branch 'develop' into attachments-tests

Conflicts:
	src/ralph_assets/tests/functional/tests_view.py
Merge pull request #385 from xliiv/attachments-tests

Attachments tests
Merge remote-tracking branch 'upstream/develop' into develop