Command line argument handling improvements & test version updates
- Add
-v1.6
&-v1.7
to recognized version flags - Add
-version
option - Mark tests introduced since version 1.6 as version 1.7
- Mark tests introduced in version 1.6 as version 1.6 & later
- Add
-help [options|tests|all]
and remove tests from default usage message - When users give invalid arguments, tell them what they did wrong