plus a lock field. The lock field was a simple "experiment locked, go away"
slot that is easy to use when you do not care about the actual state that
an experiment is in, just that it is in "transition" and should not be
messed with.

The other two state variables are "state" and "batchstate". The former
(state) is the original variable that Chris added, and was used by the tb*
scripts to make sure that the experiment was in the state each particular
script wanted them to be in. But over time (and with the addition of so
much wrapper goo around them), "state" has leaked out all over the place to
determine what operations on an experiment are allowed, and if/when it
should be displayed in various web pages. There are a set of transition
states in addition to the usual "active", "swapped", etc like "swapping"
that make testing state a pain in the butt.

I added the other state variable ("batchstate") when I did the batch
system, obvious...