Rationalize vocabulary and other editorial changes

1. Remove the rollup instance annotation 2. Reconsider allowing multiple multi-valued path segments in expand transformation 3. Add property to ApplySupported to make explicit that not all properties are groupable and aggregatable. Based on https://www.oasis-open.org/committees/download.php/51818/odata-data-aggregation-ext-v4.0-wd02-2013-12-19.2.docx Accepted: https://www.oasis-open.org/committees/download.php/51823/odata-meeting-63_on-20131219-minutes.html#odata-575