Add filters to list view (still missing form to input filtering parameters)
Use fragility as default type of assessment
Merge branch 'vulnerability-db' into filter-list

Conflicts:
	openquakeplatform/openquakeplatform/vulnerability/views.py
Filter also by country and by region
Avoid splitting import into too many lines
Better indentation in render_to_response
Fix pep8 (one line still remains too long, but it's not a big deal)
Merge pull request #175 from gem/filter-list

Add filters to the list view