Better scheme setup

[marcosgriselli]

Currently, there are schemes for testing 1 file targets: HeadlineUITests & HeadlinesMockedUITests which we could easily run by opening the file and clicking the "run tests in class" icon. On the contrary, there's no scheme for the app which can be quite misleading. Anyone that opens the project will try to run the Canillitapp target rather than a test one.

I suggest we add a scheme for Canillitapp which runs all the test targets and removes all the individual testing schemes. This will also provide us with the ability to better track code coverage.