Add support for Vue 2.0

[callumacrae]

closes #1

• [x] Change build so tests can be ran in the browser
• [x] Run tests in browser
• [x] Fix code
• [x] Test it still works with Vue 1.0
• [x] Set up CI to run tests in browser

[callumacrae]

Turns out the first step was completely unnecessary 🙄

@sobolevn Are you able to give this a quick look over? I'll merge and release as 1.0.0 😄

[sobolevn]

Sorry, I am quite busy for a little while. Nice work anyways!

[callumacrae]

no worries, tested it on a couple projects and it worked fine :)