Add async support
Add access to NLCST from `tokenize` calls
Fix bug in test
Add smarter capitalisation

This update adds better support for capitalising sentence,
by looking at the first non-punctuation node in a word, in a
sentence.

Closes GH-2.
Add smarter full-stop removal; add tests
Merge pull request #4 from wooorm/master

Fix capitalisation; fix period removal; add buffer support to all methods