added browser testing with zuul
fixed small typo introduced in last commit
added browserify and bower.json
added dependency on levelgraph to bower.json
updated README
Merge pull request #2 from elf-pavlik/feature/browserify

* [x] testing with zuul
* [x] testing Travis + Sauce Labs
* [x] browserified version in `./build/`
* [x] register with bower and add bower.json
* [x] update README