Changes

** Profile Build

* buildbot uses a "factory" to run a job

* mozharness is a single factory that can buildbot can run; within mozharness, a script is selected for a specific job. This moves the job-definition responsibility out from buildbot; by separating the pieces, you avoid excessive complexity in buildbot and also open up the possibility of running mozharness manually (e.g., by a developer, to test something)

== release simple bugs ==