Kill dead code
Fix invalid AST emit

* Mutant prevents double emits via guarding on source representation of
  partial AST nodes. Not all AST nodes are valid as roots, so this
  change creates a valid root around an leave.

* Over the time multiple of these situartions must be solved, we'll end
  up in a more deduplicated solution.

* Closes: #165
Remove dead code
Prepare version 0.5.7
Fix crash on non String {Module,Class}#name
Prepare version 0.5.8
Fix travis on cold gem installations
Update READMEs with details on rspec2/3 integration
Update travis build matrix
Set ruby version to 2.0.0 for circle
Correct YAML syntax in circle.yml
Setup ruby correctly for circleci
Whitelist reek issue
Detect memoizable instead of adamantium

* At the time the detector was wrote adamantium shipped memoization. But
  that feature was moved to the memoizable gem.

* Because mutant now uses memoizable API an explicit dependency was
  added to gemspec.
Delete memoizer on Subject#prepare
Prepare version 0.5.8
Adjust flay score
Fix whitespace
Merge branch 'master' into minitest

Conflicts:
	config/flay.yml