THRIFT-4351: use travis build stages to optimize build,
avoiding duplicate rebuilds of the same image, and also
allow personal docker hub repositories for private fork
builds to be optimized. Move ubsan build to artful image
because it catches more stuff and fix what was found.

THRIFT-4345: solidify docker build strategy for maximum
coverage: trusty, xenial, artful as stock as they can be

THRIFT-4344: add top level language summary markdown and
update readme with a new image on the layered architecture

THRIFT-3847: remove VERSION macro from config.h which
was causing a conflict on artful builds.

THRIFT-4359: fix haxe map/set decode when key is binary,
as a missing break statement caused it to use an int
during decode

This closes #1389
diff --git a/aclocal/ax_lua.m4 b/aclocal/ax_lua.m4
index 9feb352..5920167 100644
--- a/aclocal/ax_lua.m4
+++ b/aclocal/ax_lua.m4
@@ -1,5 +1,5 @@
 # ===========================================================================
-#          http://www.gnu.org/software/autoconf-archive/ax_lua.html
+#          https://www.gnu.org/software/autoconf-archive/ax_lua.html
 # ===========================================================================
 #
 # SYNOPSIS
@@ -166,7 +166,7 @@
 #   Public License for more details.
 #
 #   You should have received a copy of the GNU General Public License along
-#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
 #
 #   As a special exception, the respective Autoconf Macro's copyright owner
 #   gives unlimited permission to copy, distribute and modify the configure
@@ -181,7 +181,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 39
+#serial 40
 
 dnl =========================================================================
 dnl AX_PROG_LUA([MINIMUM-VERSION], [TOO-BIG-VERSION],