fix load test and add a test for legacy behavior
begin micro-optimization of legacy API
improve micro-optimizing
ensure legacy interface works as documented
ptidy Makefile.PL ...
Introduce API to easy specify operand and operator

A modern API (compared to legacy) has been added (with tests) to specify
exactly whether a timestamp, a DateTime object, a DateTime::Duration or
a referenced file shall be used as operator.

The operators are clearer - one can choose between modified time, accessed
time or created time, respectively. And finally, one can choose between
<, <=, >= or > as operator.
Enjoy the silence
add rule for travis