Add max column width option

Hello,

I'd like to propose the following change - option which limits the max column width. In case some table "cell" has larger length it will be wrapped by words on several lines.

What is also changed:
- Added jasmine-node specs for this option, but did not covered original behavior
- Made toString() method "public". I use it to format output of ICQ bot, so print() is useless for me
- Added examples to test.js and readme

Thanks.