Update dependencies, add missing grunt-contrib-watch dependency

* Use caret instead of ~ for safer dependency management
  * This drops support for running the build on Node 0.8
* Update SpecRunner.html to have new links for ES5 shim
  * This happens automatically when you run tests with grunt-contrib-jasmine@0.7.0
Merge pull request #46 from lazd/gruntfix

Update dependencies, add missing grunt-contrib-watch dependency