add .gitignore file
autopep8 trie.py

I'm not a pep8 nazi, but the formatting here is too much for my eyes.
only catch KeyError's from leveldb

don't hide other errors
wrap 'main' code in if __name__ == "__main__"...
use new style classes in trie.py
Merge pull request #18 from brainbot-com/cleanup-trie

Cleanup trie