LUCENE-5714, LUCENE-5779: Enhance BBoxStrategy & Overlap similarity. Configurable docValues / index usage.
Add new ShapeAreaValueSource.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1608987 13f79535-47bb-0310-9956-ffa450edef68
SOLR-6183: AbstractSpatialFieldType: refactor getValueSourceFromSpatialArgs out of getQueryFromSpatialArgs

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1608992 13f79535-47bb-0310-9956-ffa450edef68