* Proof of concept for cyclomatic complexity
* Enable configurability of rule
* Use the same nodes to increment the complexity as rubocop
* Fix typo in test description
* Properly indent code and simplify macro
* Move metric into metrics
* Cover a violation supressed by increased threshold
* Extract visitor into its own file
* Document cyclomatic complexity rule and visitor
* Refactor specs to use a macro
* Indent code inside macro
* Replace array with tuple for string formatting.
`Tuple` is stack based, whereas `Array` is allocated on the heap increasing GC pressure.
* Fix formatting
* Enable cyclomatic complexity rule by default
