Various fixes for #208
Css improvements
Longitude and latitude in model for conceptdescription
Fixes and cleanups around user event lists:
 - rationalise some templates
 - get rid of redundent 'more' action for activity list
 - handle showing/disabling of 'More' button when no events are
   available
Merge additional changes by Thibault.
Add virtual unit content type
Abstract some boilerplate for caching future responses
Revise some terminology