More updates from Hogg/Lang + speedups
More updates from Hogg/Lang + speedups

Hogg/Lang removed loop over walkers and added multilnprob function (more to come)

dfm: array resizing speedup
    - more consistent use of prob vs. lnprob
    - various formatting issues

Nice and fast... thanks guys!

johnbachman/emcee,dfm/emcee,jellis18/emcee3,ga7g08/emcee,ipashchenko/emcee-x,willvousden/emcee,ipashchenko/emcee,willvousden/emcee,farr/emcee,joezuntz/emcee,dfm/emcee,elkingtonmcb/emcee,johnbachman/emcee,drphilmarshall/emcee,linan7788626/emcee,pkgw/emcee,dfm/emcee3