Conda abstraction

This PR abstracts the conda install process to its own separate scripts that may be used from a variety of other scripts with minimal effort. This makes maintaining miniconda easier and also is a needed stepping stone for windows builds.

Working run is here: http://submit-1.batlab.org/nmi/results/details?groupBy=platform&runID=282306&groupDirection=down&sortBy=taskID&sortDirection=down&refreshTime=20