Merge RFC4 (#1865)

This commit is the result of the squashing of rfc4_dev branch in a single
commit. It implements mostly RFC 4 related work.

* Grid handling:
  - remove obsolete and presumably unfinished implementation of grid catalog functionality
  - all grid functionality is in grids.cpp/.hpp
  - vertical and horizontal grid shift: rework to no longer load whole grid into memory
  - remove hgrids and vgrids member from PJ structure, and store them in hgridshift/vgridshift/deformation structures
  - build systems: add optional libtiff dependency. Must be explicitly disabled if not desired
  - add support for horizontal and vertical grids in GeoTIFF, if libtiff is available
  - add GenericShiftGridSet and GenericShiftGrid classes, relying on TIFF grids, that can be used for generic purpose grid-based adjustment
  - add a +proj=xyzgridshift method to perform geocentric translation by grid. Used for French NTF to RGF93 transformation using gr3df97a.tif grid
  - deformation: add support for +grids= for GeoTIFF grids
  - horizontal grid shift: fix failures on points slightly outside a subgrid (fixes #209)

* File management:
  - add a filemanager.cpp/.hpp to deal with file related work
  - test for legacy proj_api.h fileapi
  - proj.h: add proj_context_set_fileapi() and proj_context_set_sqlite3_vfs_name() (fixes #866)
  - add capability to read resource files from the user writable directory

* Network access:
  - build systems: add optional curl dependency
  - add a curl-based default implementation for network related functionality
  - proj.h: add C API to control network functionality, and optionaly provide network callbacks
  - add data/proj.ini with default settings
  - add a SQLite3 local cache of downloaded chunks
  - add proj_is_download_needed() and proj_download_file()

* Use Win32 Unicode APIs and expect all strings to be UTF-8 (fixes #1765)
  For backward compatibility, if PROJ_LIB content is found to be not UTF-8 or
  pointing to a non existing directory, then an attempt at interpretating it
  in the ANSI page encoding is done.
  proj_context_set_search_paths() now assumes strings to be in UTF-8, and
  functions returning paths will also return values in UTF-8.

1 files changed, 1 insertions, 20 deletions

diff --git a/src/datum_set.cpp b/src/datum_set.cpp
index 873d7be5..15d51613 100644
--- a/src/datum_set.cpp
+++ b/src/datum_set.cpp
@@ -41,7 +41,7 @@
 int pj_datum_set(projCtx ctx, paralist *pl, PJ *projdef)
 
 {
-    const char *name, *towgs84, *nadgrids, *catalog;
+    const char *name, *towgs84, *nadgrids;
 
     projdef->datum_type = PJD_UNKNOWN;
 
@@ -118,25 +118,6 @@ int pj_datum_set(projCtx ctx, paralist *pl, PJ *projdef)
     }
 
 /* -------------------------------------------------------------------- */
-/*      Check for grid catalog parameter, and optional date.            */
-/* -------------------------------------------------------------------- */
-    else if( (catalog = pj_param(ctx, pl,"scatalog").s) != nullptr )
-    {
-        const char *date;
-
-        projdef->datum_type = PJD_GRIDSHIFT;
-        projdef->catalog_name = pj_strdup(catalog);
-        if (!projdef->catalog_name) {
-            pj_ctx_set_errno(ctx, ENOMEM);
-            return 1;
-        }
-
-        date = pj_param(ctx, pl, "sdate").s;
-        if( date != nullptr) 
-            projdef->datum_date = pj_gc_parsedate( ctx, date);
-    }
-
-/* -------------------------------------------------------------------- */
 /*      Check for towgs84 parameter.                                    */
 /* -------------------------------------------------------------------- */
     else if( (towgs84 = pj_param(ctx, pl,"stowgs84").s) != nullptr )