A shiny new Line parser with a shiny new unit test

This new Line parser sports a few features:
* Actual support for tags, though it's untested as of yet.
* Should be fully RFC and IRCv3 compliant (it was based on the psuedo-BNF).
* No regex to be found!
* Almost 30 unit tests so it is thoroughly exercised.
* Benchmarks show this is anywhere from 50-120% faster than the current parser
  and that this parser can run about 70-80k lines/sec single-threaded on an
  Intel Core i5-2435M @ 2.40GHz using CPython 3.3.1 on Linux 3.8 64-bit,
  and 725k(!) lines/sec on the same hardware/OS using PyPy 1.9.0.