Improvements to plot_monitor

* Allow calling plot_monitor programatically.
* Wildcard channel inclusion
* Option to turn off name shortening
I think the logic of this function is getting really overcomplicated. It probably would make a lot more sense to factor out a function that just plots a set of channels. Probably in a new module like pylearn2.gui.plot. Then the script, plot_monitor.py, could handle the logic of interacting with a user typing at a prompt, and the plotting module could handle just the plotting. Doing both human and programmatic access logic and drawing logic all in the same place is making it really hard to tell by visual inspection whether we correctly handle all the corner cases, like if there is only one channel in the monitor, the user types in a regular expression that doesn't match anything, etc.