updated configure.ac and README version numbers/documentation

Author: terencewtli

README.md

@@ -138,6 +138,10 @@ More data is available in the `additional_data.txt` file in the `data`
 directory.  For an extended write-up on our programs, please read the
 manual in the `docs` directory.
 
+UPDATES TO VERSION 3.1.2
+========================================================================
+Two headers were added.
+
 UPDATES TO VERSION 3.1.0
 ========================================================================
 A mode `pop_size` has been added that uses the continued fraction

configure.ac

@@ -14,7 +14,7 @@ dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
 dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 dnl General Public License for more details.
 
-AC_INIT([preseq], [3.1.1], [andrewds@usc.edu],
+AC_INIT([preseq], [3.1.2], [andrewds@usc.edu],
         [preseq], [https://github.com/smithlabcode/preseq])
 dnl the config.h is not currently #included in the source, and only
 dnl used to keep command lines short.