applied perltidy to tests
cleaned up object-related functions

 * Removed Safe::Isa dependency
 * Changed "blessed" prototype to (_)
 * Added "is_object", "class_can"
added "carpf" functions, expanded "Carp" docs
git ignore coverage stats and TODO file
removed "_::package", it wasn't a good fit anyway

There was no justification for adding this dependency:
Stash manipulation is a rather rare occasion,
compared with "Dump"ing or "List::Util" stuff.
As the previous *published* version didn't yet include this brain fart,
it could be removed safely.
improved prototypes of scalar-related functions
re-prototyped the remaining Scalar::Util functions
docfixes, simplified and expanded tests
version bump, getting ready to release
a round of Perl::Critic-guided cleanup
merge release-ready state