Update copyright, add version tags

Bump version to 1.5

Update version to 1.4

Version 1.3, August 27 2012

This version primarily fixes some bad assumptions made about how wide unicode
literals work, and adds warnings for using them directly.  This is a bit
dependent on your running build, since I don't want to write my own string parser.

Also new is support for Jython (which is actually 2.5 with an ast module available).

Version 1.2, March 8 2012

This version adds PyPy compatibility, multiprocessing support for faster
linting, has fewer false positives with bygroups(..., None, ...), and includes
many more checks for character classes.  The start and end data for a node is
also being stored separately, in preparation for partial tree reconstruction in
the next release.

Version 1.1, February 14 2012

This version adds verbose parsing, Eric's ast-based indicator, and a few more
checkers.

Version 1.0, January 3 2012

This version is tested against Pygments 1.5-dev [81d98983fd7f] and finds ~122
issues that we need to address.  At long last, I'm tagging 1.0 as the blockers
are fixed:

* The ability to check just one lexer using mod:cls (example in README)
* INFO, WARNING, and ERROR severity, with filtering on the command line
* Tests that cover all checkers
* New internal tree representation, rather than the previous list-of-tuples
  where everthing could have alternations
* Eric's new indicator code for regexes that require python code to execute to
  generate them [these show up without line numbers, but the right part of the
  pattern is indicated now, rather than a 'Y' line].
* Overlap/Gap checker gives many fewer false positives