Go to key generation (which is unimplemented) in the case where there are keys, but they're all invalid
Added capabilities discovery and workaround for bug in GnuPG < 2.1
Fixed #430. This is also a partial fix for #408.
Mock call to GnuPG in test_command to avoid network communication.

- fix for issue #570
- added mock as dependency
Merge pull request #693 from codeburg/issue_570_mock_gnupg_call

Mock call to GnuPG in test_command to avoid network communication.
Fixed #686 for people who use long key ID's but don't prepend 0x :P