Move external js files to vendor and test files to tests/tests
JSHint integration
Split test file into 3 files

* The unit tests can't pass when MessageChannel is supported
* The web workers tests can't pass when they are not implemented
* The integration tests should pass on all browsers
Define Worker.postMessage for the non polyfill version

Tests are passing on FF and Chrome
Update grunt-contrib-connect

Servers wouldn't start when specifying `*` as hostname