Extending test cases for articles module

This should make the tests more expressive then they were before. Now
the requesting and getting of information from the wordpress json api
is tested in different test cases. This should help in identifiying
possible problems during further development.
Adding flexible grid of tjschuck (960gs in sass)

Furthermore fixed the layout of the website, which was broken because
of the previous grid system with its expressive classes on the layout.
Now the grid information are mixins and included inside the sass files.