v0.4.0: ais update (#722)

* fixed squash conflicts

* removed comments

* added write_to_patch flag; fixed background image rendering

* added a rate-is-inf check to catch loglike nans

* added MCMC chains to the end of AIS for better posterior estimates

* println's to Log.info

* slicesample print statements to Log

* more printlns removed

* removed extra newline

* fixed squash conflicts

* removed comments

* added write_to_patch flag; fixed background image rendering

* added a rate-is-inf check to catch loglike nans

* added MCMC chains to the end of AIS for better posterior estimates

* println's to Log.info

* slicesample print statements to Log

* more printlns removed

* removed extra newline

* removed println