preliminary documentation and cluster.py fixes for sklearn interface changes
abotm script can now use an existing multiunit from the database by passing
the database id of the mua using the -m switch.
abotm call script changes
rate estimator changes, will now estimate the rate over the last 2.5mio samples

doc changes for RTD
rate estimator changes, will now estimate the rate over the last 2.5mio samples

doc changes for RTD