Add core.get_dir_list

doc/lua_api.txt

@@ -1704,6 +1704,11 @@ Helper functions
 * `minetest.mkdir(path)`: returns success.
     * Creates a directory specified by `path`, creating parent directories
       if they don't exist.
+* `minetest.get_dir_list(path, [is_dir])`: returns list of entry names
+    * is_dir is one of:
+      * nil: return all entries,
+      * true: return only subdirectory names, or
+      * false: return only file names.
 
 ### Logging
 * `minetest.debug(line)`

doc/menu_lua_api.txt

@@ -31,8 +31,8 @@ core.start()
 core.close()
 
 Filesystem:
-core.get_scriptdir()
-^ returns directory of script
+core.get_builtin_path()
+^ returns path to builtin root
 core.get_modpath() (possible in async calls)
 ^ returns path to global modpath
 core.get_modstore_details(modid) (possible in async calls)
@@ -59,10 +59,6 @@ core.get_gamepath() (possible in async calls)
 ^ returns path to global gamepath
 core.get_texturepath() (possible in async calls)
 ^ returns path to default textures
-core.get_dirlist(path,onlydirs) (possible in async calls)
-^ path to get subdirs from
-^ onlydirs should result contain only dirs?
-^ returns list of folders within path
 core.create_dir(absolute_path) (possible in async calls)
 ^ absolute_path to directory to create (needs to be absolute)
 ^ returns true/false