[#1298] Fix activity and about organization pages

The controller methods didn't use `self._action` which will use the
appropiate `group_` or `organization_` action depending on the group
type.

The `organization_activity_list_html` action hadn't been used at all
until now, as there was a syntax error.
[#1304] Clear and keep current database during test runs

Add option '--reset-db' to drop and reinitialize database during test
runs
[#1304] change clean_db to rebuild_db in new_test/helpers.py

Otherwise new_tests will drop and recreate database
[#1304] update docs on 'reset-db' test option
[#1304] make sure database is rebuilt during travis test runs
Merge origin/master
Install extra package needed by Jetty

See http://askubuntu.com/questions/377021/solr-jetty-on-ubuntu-12-04-3
Rename a docs page
Merge branch '1323-fix-travis-jetty'
Fix a Sphinx warning
Rebuild main.css
Merge remote-tracking branch 'origin/master' into 1304-reset-db
Merge pull request #1304 from okfn/1304-reset-db

'--reset-db' option for when running tests
[#1329] Fix wrong solr_url default in docs
Merge pull request #1329 from okfn/1329-solr_url-doc

Wrong default value in solr_url documentation
Merge branch '1298-fix-orgs-activity-about-page'