Add binary love EoS model

This MR implements the BinaryLove neutron star Equation of State model as defined in Chatziioannou, Haster and Zimmerman (2018) and as used in GW170817: Measurements of Neutron Star Radii and Equation of State.

This implementation has already been reviewed for the lalinference_o2 branch (that version was used in the papers given above) but was never pushed to either that branch or to master. It passed review by @salvatore-vitale as given at Review_of_TidalUniveralRelations. There are some minor differences between this MR and the patch given there, mostly to account for the different way tidal parameters are passed around in LALInference_master as opposed to lalinferecne_o2. There are also specific comments added to the code pointing to the implementation in the methods paper given above.

In addition to the C-code presented in this MR the review repo also contains a post-processing tool which acts on the posterior sample file and adds the transformation of the LambdaS+BLuni parameters into Lambda1+Lambda2. This is not included in this MR, and I propose to add that functionality in a separate MR later.