Workarounds for APIv1 issues
Add OPENPHOTO_TEST_SERVER_API env var

To allow testing to be restricted to a specific maximum API version.
This allows new API tests to be skipped for old servers.
Explicitly remove tags from photos during tag testing
Merge branch 'master' into apiv1_fixes

Conflicts:
	tests/test_base.py
	tests/test_framework.py
Merge pull request #34 from sneakypete81/apiv1_fixes

Apiv1 fixes