Add tests and ability to emojify flat strings

Hi, awesome project, love it and dead simple to install

However, I ended up having to coerce my template generated HTML into a DOM node, run the emojifier, then grab the innerHTML back out of it.  I didn't want to emojify in the DOM, but outside of it on the HTML strings that my template functions are generating.

This change:
- allows `<` or `>` to come before a 2char emoji, as in the test case `"<div>:)</div>"`
- spits out emojified strings of any input string, e.g., `'<div><img title=\':blush:\' class=\'emoji\' src=\'images/emoji/blush.png\' align=\'absmiddle\' /></div>'`
- adds tests!

You will probably need to:
`npm install; npm install -g testem bower coffee-script; bower install; testem;` will bring you up and running to the tester, then visit the URL it supplies. 

I wrote the tests in coffeescript as its a lot more terse when reading

Let me know if anything is incomplete or missing