bump version numbers for 1.7.2 release

configure.ac

 dnl Process this file with autoconf to produce a configure script.
 
-AC_INIT(libconfig, 1.7.1, hyperrealm@gmail.com, libconfig,
+AC_INIT(libconfig, 1.7.2, hyperrealm@gmail.com, libconfig,
 	[https://hyperrealm.github.io/libconfig/])
 AC_CONFIG_AUX_DIR([aux-build])
 AC_CONFIG_MACRO_DIR([m4])

doc/libconfig.texi

@@ -6,8 +6,8 @@
 @setfilename libconfig.info
 @settitle libconfig
 
-@set edition 1.7.1
-@set update-date 17 Nov 2017
+@set edition 1.7.2
+@set update-date 5 Jan 2018
 @set subtitle-text A Library For Processing Structured Configuration Files
 @set author-text Mark A.@: Lindner
 

lib/Makefile.am

@@ -18,7 +18,7 @@
 #
 # For more info see section 6.3 of the GNU Libtool Manual.
 
-VERINFO = -version-info 11:1:0
+VERINFO = -version-info 11:2:0
 
 ## Flex
 PARSER_PREFIX = libconfig_yy