Test PR. Having issues with running tests locally

Could be a problem with my local install; want to see if Travis will pass
this. This is the current choderalab/master, plus an empty file, so if it
doesn't pass the tests then the question becomes version numbers and such.
Maybe this gives us msmbuilder.metrics?
Removing empty tmp file
Added replica_list and ensemble_list methods

These return all the replica IDs and all the ensemble names, respectively,
by just returning the keys to the appropriate dictionaries.
Merge pull request #93 from dwhswenson/master

Test PR. Fixes problem with Travis conda requirements
Merge remote-tracking branch 'upstream/master' into sample
Merge remote-tracking branch 'dwhs/sample' into samplestorage