Total refactor of block structure and naming.

Ensure that top-level elements (body > header, body > main, body > footer)
are all wrapped in container-fluid and contain at least one row, so that
they work properly with Bootstrap CSS layout.

Rename blocks to consistently have the same name as the unique CSS class
of the element inside. Change elements to use HTML5 better: add a main
element, changed sections that are not document sections back to divs.

Remove the homepage fixture, stopped working so replaced by cms.api.create_page.

Add a thorough test suite to ensure that structure doesn't change again.
It is now fixed.
Merge branch 'master' of https://github.com/aptivate/cmsbootstrap

Conflicts:
	cmsbootstrap/tests/cmsbootstrap_tests.py