FYI: update for Python 2.7

[Michael Snyder]

I'm no expert in this stuff, but don't we need a new 2.7 entry in
this region of configure.ac?

   if test "${have_python_config}" = yes; then
     python_version=`echo " ${python_libs} " \
                          | sed -e 's,^.* 
-l\(python[[0-9]]*[[.]][[0-9]]*\) .*$,\
\1,'`
     case "${python_version}" in
     python*)
       AC_TRY_LIBPYTHON(${python_version}, have_libpython,
                        ${python_includes}, ${python_libs})
       ;;
     *)
       AC_MSG_ERROR([unable to determine python version from 
${python_libs}])
       ;;
     esac
   elif test "${have_python_config}" != failed; then
     if test "${have_libpython}" = no; then
       AC_TRY_LIBPYTHON(python2.6, have_libpython,
                        ${python_includes}, "${python_libs} -lpython2.6")
     fi
     if test ${have_libpython} = no; then
       AC_TRY_LIBPYTHON(python2.5, have_libpython,
                        ${python_includes}, "${python_libs} -lpython2.5")
     fi
     if test ${have_libpython} = no; then
       AC_TRY_LIBPYTHON(python2.4, have_libpython,
                        ${python_includes}, "${python_libs} -lpython2.4")
     fi
   fi