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
Allow -h to be used to specify the hostname

This matches the behaviour of the other commandline tools.
Since this is a bit non-standard, the usage message now specifically mentions the --help option.
Also added a check for excess arguments.
Merge branch 'master' into apiv1_fixes

Conflicts:
	tests/test_base.py
	tests/test_framework.py
Merge pull request #33 from sneakypete81/class_config_cli_tweaks

Allow -h to be used to specify the hostname
Merge pull request #34 from sneakypete81/apiv1_fixes

Apiv1 fixes