updates pyne fast and pyne nightly to use conda

hi all,

this should employ conda instead of manual builds for our nightly and CI runs.

I think the next steps are
* kill the current nightly cron job on batlab and restart after a pyne-ci repo update
* kill the polyphemus server, update pyne-ci repo, restart server

Whomever does these tasks, could you please add the appropriate steps to the pyne-ci readme?