replaced local gtk m4 test with AM_PATH_GTK_2_0 also changed AC_CHECK_LIB to AC_SEARCH_LIBS to avoid extra libs in compile lines.

moved socket_accept and socket_readable functions into a common place for all the calls since the code was very similar.

   in sattach.c, step_launch.c, and allocate_msg.c

job_desc_msg_t - in, out, err have been changed to std_in, std_out, and std_err respectfully.  Needed for PySLURM, since Python sees (in) as a keyword.