Upgraded version number to 0.4.0 following the inclusion of the GIZMO-SPH branch into the master.

configure.ac

@@ -16,7 +16,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Init the project.
-AC_INIT([SWIFT],[0.3.0])
+AC_INIT([SWIFT],[0.4.0])
 AC_CONFIG_SRCDIR([src/space.c])
 AC_CONFIG_AUX_DIR([.])
 AM_INIT_AUTOMAKE