Adding tests to javascript form factor

Added some unit tests to GWT MVP Client in Javascript

Changed a little bit the code to make it more testable (with some DI)
Tests are ran with maven with jasmine maven plugin
if you want to run the tests manually while developping : mvn jasmine:bdd (Awesome tool btw!)

Changed the POM so it specifies the sourceLevel, it prevented intelliJ from compiling without it.