Generalize bandpass

[bcipolli]

This takes the tests/test_bandpass.m script, and generalizes it into a callable function.

EDU>> bandpass_by_task(10, 2, '../34x25/sergent_1982/uber_sergent_args', 'sergent_1982/de/sergent', {}, {'runs', 5})

• Arg 1: # of frequency steps to take. This will take steps of 1.7 cycles/image (34/2 /10)
• Arg 2: width of window (in terms of frequency steps). 3.4 cycles/image here.
• Arg 3: path to the argument file that you want to load.
• Arg 4: string for the experiment you want to run.
• Arg 5: any 'override' options
• Arg 6: any 'override' args.

[bcipolli]

@vishaalprasad this is ready for review. Note that if you zoom into the error difference at higher frequencies, you do see the cross-over here :) Also cool to see the interaction change with different bandpass filters; all the task-related graphs are produced using this method.

[vishaalprasad]

Looks good!