v1.2

Changes

• TheJoker now expects a numpy.random.Generator instance instead of a
  RandomState for controlling random number generation.

• Renamed t0 to t_ref in places where it actually represents a reference
  time.

• Added functionality to compute t0, i.e. the time of phase=0, for samples.

• Added functions to compute time-sampling statistics for the samples returned
  from The Joker (see: thejoker.samples_analysis).

• Fixed a bug in the UniformLog distribution that affected running MCMC.