Add a couple more tests for varint encoding

git-svn-id: http://svn.osgeo.org/postgis/trunk@12846 b70326c6-7e19-0410-871a-916f4a2858ee
Stub lwout_vt.c
Complete drawing methods for core types
Fix build, export VT functions to header file
Implement sql side of ST_AsVT_Geometry
Fix handling of tolerance parameter
Stub unit test for vt output
Fix encoding of command count
Fix leak in vt encoder
Add test for encoding a linestring