configure.ac: bump version to 3.7.15

Author: rrthomas

configure.ac

@@ -3,7 +3,7 @@
 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ([2.71])
-AC_INIT([recode],[3.7.14],[rrt@sc3d.org])
+AC_INIT([recode],[3.7.15],[rrt@sc3d.org])
 AC_CONFIG_SRCDIR(src/recode.c)
 AC_CONFIG_AUX_DIR([build-aux])
 AM_INIT_AUTOMAKE