Adding support for additional / custom reporters

* bumped version
* Refactored a few things to make the report outputting more common.
* New concept of reporter
  - previously had ContextOutput and SummaryOutput
  - these have been separated out as individual reporters
  - additional CheckstyleOutput reporter created
* Added extra (optional) command line params
  - require
      allow specifying reporters from outside
  - report-dest
      passed in to reporters through a call to destination attribute and
      expected to be used to specify e.g. output file location
  - reporter
      takes the class name (qualified) of the reporter to use
      e.g. FoodCritic::ContextOutput, FoodCritic::CheckstyleOutput
* Added source attribute to rule DSL, automatically populated as the source
  file/line of the rule block, providing a common attribute to look at to
  obtain that info
* Altered the rake task to allow propogation of options into the reporter