Better word separation

Hello there!

Very neat stuff!  I noticed that squirt wasn't separating words out very intelligently, and wanted to lend a hand.

This pull does two things:

1. It separates words based on all whitespace characters (tab, newline).  Previously, they were split by only spaces.

2. It splits up words with non-whitespace characters, such as punctuation.  Because of the way that `textContent` works, adjacent words that are wrapped in tags (e.g. `<b>This,</b> and this`) will get returned as single words (`['This,and', 'this']`).  This pull adds an extra space after all punctuation, which often helps with words that run-together.

Thanks!

/cc #10, #17