Added tip5pe water model to oplsa.

The model introduces a small modification to the tip5p model
to reproduce better experimental data for simulations using
Ewald summation.

Reference publication J. Chem. Phys. 120 (2004) 6085-6093.

Fixes #1016.

Change-Id: I1afba614d65d1e4e8eb8594e99eea41e31f1e391