Adding date stamped and form code to contact forms

Contact forms may now be date-stamped.  If this date is recorded during
data entry then a "consent to contact stamped" event will be added to
the participant (if the event exists).  Additionally, a new "grouping"
column has been added to the participant table which is defined by the
code selected during the data entry phase.
Fixing bug in last update
Merge remote branch 'origin/release' into develop