bug-fix: typist language issue

- a typist with language 'any' was getting all participants
  whose language was NULL.  Only one typist had 'any' language
  and to no sibling assignments were created.  Fix this by
  using IFNULL on participant.language and set it to 'en'
bug-fix: patch missed some assignments

- original patch only found assignments with no
  adjudications regardless of end_datetime status and
  so missed any assignments with non null end_datetimes
  that contained test_entrys flagged as adjudicates: set
  the end_datetime to null for all assignments with any
  test_entrys requiring adjudication
doc: minor style and doc fixes
bug-fix: deferrals and their reversals

- ensure that the assignment end_datetime remains NULL until
  all tests are complete without a deferred status
- fix patch to identify cases where deferral processes failed to
  set assignment end_datetime to null
Merge remote branch 'origin/release' into qa

Conflicts:
	api/database/assignment.class.php