flav-io/flavio v1.1

The first minor release in the v1.x series brings a couple of new observables and some other improvements. Many of these improvements where motivated by smelli and special thanks go to Jason Aebischer, Jacky Kumar, and Peter Stangl. New observables More leptonic LFV τ decays: τ→3e, τ-→e-μ+μ-, τ-→e-μ+e-, τ-→μ-e+μ- τ→πl and τ→Kl (implemented by @jackypheno) KS→πlν Other improvements Improved treatment of likelihoods of τ LFV limits Implemented the B form factors from a combined fit to an improved LCSR calculation and LQCD results in arXiv:1811.00983. These form factors have been made the default for B→π and B→K. Updated all particle masses and widths to PDG 2018 values Other parameter updates: fK and fπ from FLAG; B bag parameters now use the FLAG average for the SM operator Consistent treatment of scale dependence of longitudinal meson decay constants (implemented by @peterstangl) Fixes A missing factor of 2 in the dipole contribution to τ→3l was fixed (thanks to Andrzej Buras [yes!] for noticing this