Use as command arguments the remaining parameters

This change allows execute st as 'st mutt' while it keeps the
compability with xterm and urxt.

st.c

@@ -4008,7 +4008,8 @@ void
 usage(void) {
 	die("%s " VERSION " (c) 2010-2015 st engineers\n" \
 	"usage: st [-a] [-v] [-c class] [-f font] [-g geometry] [-o file]\n"
-	"          [-i] [-t title] [-w windowid] [-e command ...]\n", argv0);
+	"          [-i] [-t title] [-w windowid] [-e command ...] [command ...]\n",
+	argv0);
 }
 
 int
@@ -4027,12 +4028,8 @@ main(int argc, char *argv[]) {
 		opt_class = EARGF(usage());
 		break;
 	case 'e':
-		/* eat all remaining arguments */
+		if(argc > 1)
-		if(argc > 1) {
+			--argc, ++argv;
-			opt_cmd = &argv[1];
-			if(argv[1] != NULL && opt_title == NULL)
-				opt_title = basename(xstrdup(argv[1]));
-		}
 		goto run;
 	case 'f':
 		opt_font = EARGF(usage());
@@ -4059,6 +4056,12 @@ main(int argc, char *argv[]) {
 	} ARGEND;
 
 run:
+	if(argc > 0) {
+		/* eat all remaining arguments */
+		opt_cmd = argv;
+		if(!opt_title)
+			opt_title = basename(xstrdup(argv[0]));
+	}
 	setlocale(LC_CTYPE, "");
 	XSetLocaleModifiers("");
 	tnew(MAX(cols, 1), MAX(rows, 1));