Deactivate rubocop guard

Somehow it disables the rspec guard, and this one is more important for
me
Refactor strategy CLI parsing

* Add CLI::Builder::Rspec
* Remove defunct static stragies
* Add --rspec-level argument
Code style
Fix warnings in Mutant::CLI
Fix warnins in subject and mutation runner
Remove --profile flag from rspec

Rationale:
* Console output lines are limited
* The more "valuable" information I see at once (without scrolling) the faster I'am
* I'm normally not in "tuning" mode.
* Can always add it when I need to tune. (But in this cases I'll profile
  most likely)
Fix warnings in literal range mutator
Add support for mutating start and end nodes for range literals
Fix warnings in Mutator::Node::Send
Use better nameing
Fix warning in Mutant::CLI
Remove unneeded double negation