Add new unit tests related to the #279 issue.
Note that the signature is 
SELECT ST_ZUpdateLineExtremities('LINESTRING(0 0 , 5 0 1, 10 0 )'::GEOMETRY, 0, 20, false);
or 
SELECT ST_ZUpdateLineExtremities('LINESTRING(0 0 , 5 0 1, 10 0 )'::GEOMETRY, 0, 20, true);.

and not a string parameter for the last argument.
Fix kml gx tag extension
Fix unit tests for ST_Delaunay please read #283
Improve ST_ConstrainedDelaunay tests
Add function ST_Is3D please read #70