GiST and SP-GiST GiST and SP-GiST n-D indexes (based on GIDX) with overlaps, contains, within, and equals operators

Files not added in previous commit.

Patch by Esteban Zimányi and Arthur Lesuisse from Université Libre de Bruxelles (ULB)

Closes #4230



git-svn-id: http://svn.osgeo.org/postgis/trunk@17002 b70326c6-7e19-0410-871a-916f4a2858ee

Author: Komzpa