To make it easier to create a bunch of threads in a single
call (and stop them in a single call) create a concept of
a thread bundle (similar to a thread group) that will call
into a provided set of factories to get a thread, activate
callbacks to notify others that a thread is about to start
or stop and then perform the start or stop of the bound
threads in a orderly manner.
Change-Id: I7d233cccb230b716af41243ad27220b988eec14c