libproj: add new fns to dox

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@72525 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/proj/projlib.dox

@@ -107,5 +107,11 @@ default: cmd
  - GPJ_osr_to_grass()
 
  - GPJ_wkt_to_grass()
+
+ - GPJ_init_transform()
+
+ - GPJ_transform()
+
+ - GPJ_transform_array()
 */