Get prepared for functional testing

So we decided to do functional testing, as opposed to unit and integration testing, for the osmtm application. This PR is a step in that direction. It shows how to do functional testing, with functional tests for the `/project/{project}` web service as an example.

Note that the tearDown function abort the transaction. In this way we do not actually inserts records in the database, and thereby avoid the costs associated to table creation and dropping for each test.

(See http://docs.pylonsproject.org/projects/pyramid/en/latest/narr/testing.html for a discussion on unit testing vs integration testing vs functional testing.)