port check_func(s) from rra as shown in issues#5

rra showed in issue#5 two functions relying on action-if-true/false, port
them before grand API consolidation starts.
Added simple tests for both to ensure they're working.

Bonus: We have more tests whether the link stage works as expected ...
Perl::Tidy tests to help autarch with issue#4
refactor all basic checks to a unique API

instead of having dozen of familiar optional arguments, add an option
hash as last argument to almost each function which contain action_on*
functions with clear meanings.