Update the readme and scripts to reflect zuul instead of tidepool-groupedit

I preserved the old addToCareteam.sh script as addToCareteamGroupedit.sh so that it is simple to have users use the old script if they have problems with the new one for some reason.
Merge pull request #15 from tidepool-org/cheddar/readme-and-scripts

Update the readme and scripts to reflect zuul instead of tidepool-groupedit