Add the fx-desktop channel & start to set up front end unit tests.

* Add mocha & chai to the bower config.
* Add a functional test shell for the confirm screen.
* Go to the correct page on startup if the browser supports Fx events.
* Mocha tests now run as part of the intern functional tests.
Merge pull request #191 from shane-tomlinson/issue-189-fx-native-glue

fx-desktop glue & start to set up front end unit tests.