Update list of installed experiments after adding or removing an experiment
Update list of installed experiments after adding or removing an experiment

Fixes #723.

fzzzy/testpilot,6a68/idea-town,6a68/testpilot,mozilla/idea-town-server,flodolo/testpilot,lmorchard/testpilot,mozilla/idea-town-server,ckprice/testpilot,chuckharmston/testpilot,ckprice/testpilot,mozilla/idea-town,6a68/idea-town,ckprice/testpilot,6a68/idea-town,lmorchard/idea-town,mathjazz/testpilot,chuckharmston/testpilot,lmorchard/testpilot,fzzzy/testpilot,clouserw/testpilot,lmorchard/idea-town-server,mozilla/testpilot,mozilla/testpilot,6a68/testpilot,mozilla/idea-town,mozilla/idea-town,meandavejustice/testpilot,flodolo/testpilot,dannycoates/testpilot,lmorchard/testpilot,meandavejustice/testpilot,mozilla/idea-town-server,lmorchard/idea-town-server,lmorchard/idea-town-server,ckprice/testpilot,6a68/testpilot,flodolo/testpilot,clouserw/testpilot,mozilla/testpilot,meandavejustice/testpilot,mozilla/idea-town-server,dannycoates/testpilot,fzzzy/testpilot,mathjazz/testpilot,fzzzy/testpilot,mathjazz/testpilot,chuckharmston/testpilot,flodolo/testpilot,clouserw/testpilot,clouserw/testpilot,dannycoates/testpilot,dannycoates/testpilot,lmorchard/idea-town-server,chuckharmston/testpilot,lmorchard/testpilot,6a68/testpilot,mathjazz/testpilot,meandavejustice/testpilot,lmorchard/idea-town,lmorchard/idea-town,mozilla/idea-town,lmorchard/idea-town,6a68/idea-town,mozilla/testpilot