convert tests to intern and add travis ci

[neonstalwart]

this converts the tests to use intern so that they can be run in browsers on saucelabs via travis. the environments i've chosen for testing are kind of arbitrary so they probably need to be tweaked.

i created a persvr-ci saucelabs account and those are the credentials i've used in .travis.yml but those can easily be change to any other account.

i've also added 3 scripts in package.json to help with testing

• npm run test - runs the tests from the command line. does not involve browsers
• npm run test.proxy - runs a proxy to serve tests locally. visit localhost:9000/__intern/client.html?config=test/intern to run the tests after starting the proxy.
• npm run test.sauce - runs the tests on saucelabs. you can run this locally as long as you set environment variables for SAUCE_USERNAME and SAUCE_ACCESS_KEY

this PR also closes #40

[neonstalwart]

i've added further support to work in older JS environments that don't support Array methods. IE8 has been added to the environments being tested by CI.

[kriszyp]

Can you check to make sure my changes to the paths in intern.js didn't screw anything up for you?

[kriszyp]

And thank you for this great commit!