Check for unnecessary new lines.

I'm not proud of this code. Cane is an awesome tool with a shitty API for extensions (IMO). What I often find myself asking for is:

* name of the file
* path to the file
* current line number
* previous line number
* next line number
* first line
* last line

The best that Cane offers is an enumerator for the current file holding each line. This sort of works because it provides the first 3 items in my list but makes the others hard to get to.

IMO we have 3 choices - continue working with this API, fork cane and build the API we want (and submit the changes back) or write our own version of cane specifically targeting our styleguide.

I'm interested to know what people think.