patch 7.4.2137

Problem:    Using function() with a name will find another function when it is
            redefined.
Solution:   Add funcref().  Refer to lambda using a partial.  Fix several
            reference counting issues.

src/vim.h

@@ -2475,6 +2475,7 @@ int vim_main2(int argc, char **argv);
 #define ERROR_DICT	4
 #define ERROR_NONE	5
 #define ERROR_OTHER	6
+#define ERROR_DELETED	7
 
 /* flags for find_name_end() */
 #define FNE_INCL_BR	1	/* include [] in name */