module to handle subtest failures with exceptions

 Test::Abortable provides a simple system for catching some exceptions and
 turning them into test events. It provides a means to communicate, via
 exceptions, that the running subtest should be aborted, possibly with some
 test output, and that the program should then continue.
 .
 Test::Abortable exports a subtest() routine that behaves like the one in
 Test::More but will handle and recover from abortable exceptions. It also
 exports testeval(), which behaves like a block eval that only catches
 abortable exceptions.