Add cunit tests for twkb

git-svn-id: http://svn.osgeo.org/postgis/trunk@12867 b70326c6-7e19-0410-871a-916f4a2858ee
Move varINT function to header file for performance reasons

git-svn-id: http://svn.osgeo.org/postgis/trunk@12868 b70326c6-7e19-0410-871a-916f4a2858ee
Fix typo

git-svn-id: http://svn.osgeo.org/postgis/trunk@12869 b70326c6-7e19-0410-871a-916f4a2858ee