new thorn for initial data (Hydro_RNS)

[Roberto De Pietri]

The LSU and Parma groups used for publications and contributed to the development of the thorn the generate initial data for Rotating-Neutron-Star RNS based on Nik Stergioulas code (http://www.gravity.phys.uwm.edu/rns/) which constructs models of rapidly rotating, relativistic, compact stars using tabulated equations of state which are supplied by the user or polytqopic EOS. The code was widely used in conjunction with the Whisky code and more recently with GRHydro.

The relevant code can be found here:

[https://bitbucket.org/GravityPR/prthorns/src]

I'd like another developer to have a look and give input. Once/If this is deemed ok to be included on technical grounds, we will add the necessary documentation. Test suites and example are already present.

Keyword: parma