Set version to 1.3-alpha to reflect Dani's merge of the BM-branch.

configure.ac

 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ(2.52)
-AC_INIT([alberta], [1.2-pre8], [claus@mathematik.uni-freiburg.de])
+AC_INIT([alberta], [1.3-alpha], [claus@mathematik.uni-freiburg.de,koester@math.uni-augsburg.de])
 
 AC_CONFIG_SRCDIR([ALBERTA/src/Common/alberta.h])
 AM_MAINTAINER_MODE