replace a call to extract_case_blocks with get_case_updates

get_case_updates has a normalized return form
whereas extract_case_blocks depends on the version
to return and accept the normalized model (CaseUpdate)
than the raw json
Merge pull request #144 from dimagi/get_case_updates

replace a call to extract_case_blocks with get_case_updates
include @items in OTA restore to enable progress bar on mobile
fix tests (add @items attr to response envelope)
Merge pull request #145 from dimagi/items

Support for response size (mobile progress bar for restore)
Merge branch 'master' into commtrack