tip4-tip4 real space interaction


git-svn-id: https://svn.ices.utexas.edu/repos/clsb/trunk/moil@4815 90e2fc84-bd37-0410-82f1-ae2f889bfac2
further development tip4p


git-svn-id: https://svn.ices.utexas.edu/repos/clsb/trunk/moil@4816 90e2fc84-bd37-0410-82f1-ae2f889bfac2