Updated the readme to reflect changes made to the linter.
Added a bit more control over how and what should be linted.
Changed the regex to contain both the column start end column end for the error. This is later used to set the correct length of the error box. (near)
Made the 'main message' optional since it doesn't always exists in flows error messages.

Cleaned the output and changed the formatting of the linted message. This is mostly a proposal.