Revert 6e5720

From pylearn-dev:

> Commit 6e5702 (written by Madison, reviewed by Fred and Xavier) changes the interface of train.py. Previously, models were saved immediately after running monitoring, so that the last monitoring channels in the pkl file are derived from the parameters in the pickle file.
i.e., the order was monitor, train, monitor, save, train, monitor, save...
Now it is
monitor, train, save, monitor, train, save, monitor, train, save...
This is bad because the monitoring channels appear to be incorrect (we've had a lot of e-mails on the mailing list saying that compute_test_err.py doesn't match the monitor, maybe this is why) and because it means that it takes one extra epoch before updates are visible to the plot_monitor.py script.
Please restore the original interface ASAP and add unit tests to make sure this doesn't happen again.