Added iAMOEBA water parameters

This PR adds the iAMOEBA water model; I should have done this a long time ago. :)  

There might be several researchers from the Biophysical Society looking for these parameters, so hopefully we can add them to the 6.0 release - if not, no sweat.  

I understand it is not a critical bug fix, so if granted, this would be a favor and an exception to the rule.