Support for Cane metrics (fixed)

Resubmitting Pull Request #48 for adding [Cane](https://github.com/square/cane) to MetricFu:
* Fixed typo in report
* Version upgrade in separate commit

Cane can be configured using the following options:

```
MetricFu::Configuration.run do |config|
  config.cane = {:abc_max => 15, :line_length => 80, :no_doc => 'y'}
end
```