Change reek configuration to use devtools default as base
Update metrics configuration
Rename spec to use the name defined in mutant for #[]
Refactor spec to use around block instead of a before/after pair
Update freezer to handle anonymous modules
Remove unnecessary argument

* If the constant is found by const_defined?, it can only be done
  when the constant is defined within the given namespace. So then
  when the constant value is returned it is guaranteed to be in the
  namespace, so the extra argument is redundant.
Add spec to kill mutation
Add spec to kill mutation
Update flay threshold