Merge branch 'develop' of ssh://cdetux2.unibe.ch/var/local/git/lmkp/lmkp into develop

Conflicts:
	lmkp/__init__.py
Improved filtering (so far, only __eq), added sorting (numbers treated as strings)
Filtering with all operators, respects number values
Remodeled querying. Fixed bug preventing filtering by number and string at same time.
Sorting now correctly handles multiple entries of sort attributes for same activity.
Added possibility to provide own filter and UID.
Merge branch 'feature/AP2' into develop
Merge branch 'develop' of ssh://cdetux2.unibe.ch/var/local/git/lmkp/lmkp into develop
Add centroid point of activities to the map
Add syncronization between features on the map and the filterpanel
Merge branch 'feature/showgeometry' into develop
Bugfix the sync between features on the map and the filterpanel
Add GeoExt action
Activity query now localized. Encountered bug preventing correct handling of Activity diffs
Version now also in Ext model of Activity, gets submitted when creating new TagGroup
Modified datamodel (include previous_version in Changesets)
Activity diffs now working
Fixed small bug.
Merge branch 'feature/activity_history' into develop

Conflicts:
	lmkp/static/app/controller/Filter.js
	lmkp/static/app/model/Activity.js
Add GeoExt.Action