Added promise-like functionality

[beatgammit]

Thanks so much for your work on this module!!

I made some changes, most of them aesthetic, but I did make one big change; I added promise-like functionality to eachLine.

Now, when you call the eachLine function, you can call .then() and pass a callback, which will get called after the last line has been read. This isn't exactly like promises, but it's pretty close.

I also:

• Made everything compatible with JSLint and strict mode
  • I had to change spaces to tabs. JSLint puked on some indentation, and this was simpler (and my editor was already set to use tabs).
  • Regex it if you like- :%s/\t/ /g in vim
• Moved some things around to make it cleaner (just a few lines, not much)
• Updated the README
• Bumped the version in package.json
• Added a version tag

Everything should be backwards compatible so this should just be a drop-in replacement. I just needed the promise-like functionality.

[nickewing]

Thanks for your contribution!