Copied bibstuff's latex codec.
Substituted input -> input_ in latex codec code for pep8.
Fixed latex codec to use the CodecInfo class, added regression tests.
Register latex codec on extension plugin import.
Reimplemented inputenc, added tests for it, refactored codec info construction.
Updates for error handling, incremental interface, and bugfixes:

* Latex_encode now accepts 'strict', 'ignore', and 'replace' errors

* Implemented incremental encoder and decoder interface, and added tests for
  them.

* Fixed a bug when trying to _unlatex an empty byte string.
Small updates, encoder test now has newlines as well for better coverage.
Another small bugfix, and bibtex files are now parsed with the latex codec.
In latex codec: marked equivalents from other latex packages.
Added another test.
Initial simple tex lexer, reorganised tests.
Fix for Python 2.6, update lexer test for nose.
Anther few small bugfixes for Python 2.6, moved codec tests to separate module.
Comment lexer tests, fixed a bug in lexer.
Lexer also yields token names, improved testing.
More efficient character matching, will also more easily allow multibyte encoded latex input (such as unicode).
Implemented lexer buffering, so it can be called incrementally.
Error handling, unicode decoding.
Lexer improvements, token tests.
More lexer improvements, and implemented initial incremental decoder using the new lexer.