time_frequency.AverageTFR.plot() disabling interpolation

Hello everyone,

This is regarding the use of time_frequency.AverageTFR.plot() function.

Since it's hard to see the individual frequency responses with interpolated
plots, it would be very good if you could set the default interpolation
behavior to 'none', or give an option for users to turn it off.

The following code will disable the interpolation:
In function _imshow_tfr() of mne/viz/topo.py (line 193):

add the following argument while calling ax.imshow():
interpolation='none'

Could you apply the changes or at least give an option to disable the
interpolation?
Thanks a lot!

Best,
Kyuhwa