Minor bugs

[doliinychenko]

Running the Example.ipynb notebook I encountered some minor bugs:
line 166, mcmc.py: logging.info('running %d walkers for %d steps', self.k, nsteps) crashed, because self.k member is absent
line 426, mcmc.py: storechain argument is actually absent in run_mcmc
line 426, mcmc.py: X0 = sampler.run_mcmc()[0] complains that X0 is 'not subscriptable'. After removing [0] it seems to run fine.

[raymondEhlers]

Hi @doliinychenko , thanks very much for the report, and sorry for the extremely slow response! I think that all of these issues are due to the emcee version. The interface changed from version 2 -> 3, and the package still depends on version 2.1.1. We list this in the requirements.txt, but the better solution would be to update to be compatible with the newer API. So I'd suggest leaving this issue open so don't forget to resolve it