Specify canonical form of entity-id

Slightly modified proposal: By convention, the entity-id does not end with a cast segment even if the entity type is part of an inheritance hierarchy. The canonical representation of the edit/self link is the id plus the cast segment [as required] The canonical representation of the navigation link is the self link plus the navigation property The canonical representation of the association link is to append /$ref to the navigation link. This simplifies rules by putting the cast segment on the self link rather than conditionally applying it to each navigation property/advertised function/etc.

Core: https://www.oasis-open.org/committees/document.php?document_id=49675&wg_abbrev=odata JSON: https://www.oasis-open.org/committees/document.php?document_id=49674&wg_abbrev=odata Atom: https://www.oasis-open.org/committees/document.php?document_id=49673&wg_abbrev=odata Accepted: https://www.oasis-open.org/committees/download.php/49679/odata-meeting-43_on-20130624-minutes.html#odata-441