Removed very old regression feature

I can't see a way to unit test this regression in a meaningful way, and
I'm not convinced of the value of keeping regressions as features.
Pulled out tag limiting from cli legacy feature

Also took the opportunity to standardize the tag filter feature a little
further.
Merge pull request #481 from chrismdp/remove_bug_600_feature

Removed very old regression feature
Merge pull request #483 from chrismdp/pulled-out-tag-limited

Pulled out tag limiting from cli legacy feature