add case.to_extended_dict() for case display
refactoring:

- extract display definition into model
- allow casexml users to define wrap behavior with a django setting
rename to_extended_dict -> to_full_dict
move commtrack-specific case stuff to commtrack cases
move some code to enable automatic wrapping of different case types
add class/doc_type check to test
last attempt to fix automatic wrapping before backtracking
revert automatic case wrapping and changes that depended on it
get correctly wrapped case in case display
hide case properties tab if there aren't any
don't break when CASE_WRAPPER setting isn't defined
Merge pull request #53 from dimagi/extended-case-display

Extended case display