Tested and improved

OK, I've fixed the code so that it runs now with the following performance.
It takes ~170 seconds to parse a corpus.
Only the verb *disqualify* doesn't get parsed. No exception is visible in the log, but my hunch is that there's something memory-related going on there.
It takes ~ 2.5 seconds to pickle a parsed corpus and ~7-8 seconds to load a pickled parsed corpus.

To-Do still:
- [ ] I was thinking of turning some to the methods in the VALEXCorpusReader class into class methods as opposed to instance methods. This would allow the user to load individual verb files without having to parse a whole corpus. What do you think about that?

- [ ] Doc-strings need to be created...

- [ ] We may want to start thinking about parsing this stuff further. I have a lisp repl script lying around somewhere, we could use that as a base for writing a small (and fast!) parser for the expressions because it's basically the same principle of nested parentheses. Or we can use PLY, I'm down for learning how that works too!