* On installs with GUA and ULA's we should prefer ULA's as it's been demonstrated that GUA's can and often are rotated by ISPs. Fixes#1473
* Add test for link-local address detection
* Add ULA-only and GUA-only tests
* Add test_IPv6_GUA_ULA_test and test_IPv6_ULA_GUA_test
* Add ""
* Add mock_command_2 command that can mock a command with more than one argument (as "ip -6 address") and result multiple lines of results
* Make mock_command_2 more similar to the original mock_command
* Correct comments
* Fixed remaining comments
* Fixed one last comment...
* Fixed a comment...