Tracker numbers: 3398, 3399, 3406, 3592, 3648, 3649, 3702, 3763
Many updates to the Encounter resource as per the above list of tracker items.
(Plus the inclusion of the StatusHistory component defined by PA over the last few weeks)

git-svn-id: http://gforge.hl7.org/svn/fhir/trunk/build@3786 2f0db536-2c49-4257-a3fa-e771ed206c19