* New primary interface #call makes specs and implementations much
easier
* We had #each mostly for historical reasons that are not relevant
anymore
* Mutation covers the Mutant::Matcher namespace
* No easy way to insert mutants on these via current monkey patching
loader
* The blocks are typically part of a method building library when those
libraries are mutated the def/defs nodes will be part of an mutated
block that is included in a subject.
[fix#254]