Service release

New features:

• plots: network plots can now be plotted using a given Axes object.
• thermo: TRAM supports the new parameter equilibrium which triggers a TRAMMBAR estimation.
• thermo: the model_active_set and msm_active_set attributes in estimated MEMMs is deprecated; every
  MSM in models now contains its own active_set.
• thermo: WHAM and MBAR estimations return MultiThermModel objects; return of MEMMs is reserved for
  TRAM/TRAMMBAR/DTRAM estimations.

Fixes:

• coordinates: MiniBatchKmeans with MD-data is now memory efficient
  and successfully converges. It used to only one batch during iteration. #887 #890
• coordinates: source and load function accept mdtraj.Trajectory objects to extract topology. #922. Thanks @jeiros
• base: fix progress bars for modern joblib versions.
• plots: fix regression in plot_markov_model with newer NumPy versions #907. Thanks @ghoti687.
• estimation: for n_jobs=1 no multi-processing is used.
• msm: scale transition path times by time unit of MSM object in order to get
  physical time scales. #929