Add duration, time zone, start, end, location and all day attributes to the calendar item
Add method calendar_items_between
Adjust the field_uRI used for searching using the calendar_items_between method to use calendar:Start and calendar:End
Merge branch 'expand-calendar-item-attributes' of https://github.com/tdm00/Viewpoint into tdm00-expand-calendar-item-attributes
Fixes #100: move calendar_items_between to calendar_folder
* rename to #items_between to keep same signature
Merge branch 'tdm00-expand-calendar-item-attributes'