Inflexible line length limits considered harmful

* Relaxes the line length limit to 160
* As a correctness test, changed something that is arguably better on one line than two
README describes test suite and pull req. guidelines
* how to run specs;
* how to avoid a torrent of errors if you use Boot2Docker and have your env. vars set;
* why and how of cane
  * Please read the section under 'Style Checks' -- is that the correct policy people should follow on a failing style check?