added missing include for linux

modules/mol/base/src/impl/atom_prop.cc

@@ -16,6 +16,7 @@
 // along with this library; if not, write to the Free Software Foundation, Inc.,
 // 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 //------------------------------------------------------------------------------
+#include <algorithm>
 #include "atom_prop.hh"
 
 namespace ost { namespace mol { namespace impl {