Modified the behavior of "gds read" (and by extension "cif read")

so that it does not fail if an edit cell is not loaded, but
simply loads the default unnamed edit cell.  This is somewhat bad
behavior in the case of reading GDS, since if the GDS is a library
and does not have a top level cell that matches the name of the
GDS library, then the edit cell that is loaded when the "gds read"
command is issued remains unchanged, so it didn't need to be there
in the first place.  Fixing this to behave better would require a
bit of additional work.

commands/CmdCD.c

@@ -998,6 +998,11 @@ CmdCalma(w, cmd)
 			cmd->tx_argv[2], cmd->tx_argv[2], cmd->tx_argv[2]);
 	        return;
 	    }
+
+	    /* Ensure that there is a valid edit cell */
+	    if (EditCellUse == NULL)
+		DBWloadWindow(w, (char *)NULL, DBW_LOAD_IGNORE_TECH);
+
 	    CalmaReadFile(f, namep);
 	    (void) FCLOSE(f);
 	    return;