Revert "Revert "XLALGenerateSimBurst():  move peak time initialization here""

This reverts commit 88790ee1fdb6cd9055e14030a1c0802ff6f9e551, but fixes it, too.
PNCoeffs: Add the TaylorT2 dt/dv coefficients and spin-spin flux terms
(Spin)TaylorF2/PNCoeffs: Combine spin-spin terms into rest of phasing interface
Add test for TaylorF2 terms in PNCoefficients

Test that phasing, dtdv, and energy/flux are all consistent.