[Users] w_lorentz factor in TOVSolver external.inc

[Bruno Coutinho Mundim]

>>> After looking at the equations carefully yesterday, I would strongly
>>> suggest that you apply your patch to all definitions of w_lorentz_2 in
>>> external.inc. The equations there do follow the Valencia formulation as,
>>> for example, it appears in eqs. 26 and 27 of Font et al's paper
>>> (gr-qc/9811015).
> Attached please find an updated version of my original patch that 
> hopefully catches all occurrences of the Lorentz factor.
> Bruno, Frank: does this look ok to you?
> 
It looks good to me!

>> You could add comments to the code, either to the definitions of these 
>> variables or to the overall README.  Pointing to literature in the 
>> code will help future readers a lot.
> I added the references and definition to param.ccl and some notes to the 
> code.
> 
> Ok to commit?
> 
Yes!

Cheers... Bruno.