BLD: fix doc build on ReadTheDocs, need matplotlib for plots in examples.
BLD: fix doc build on ReadTheDocs, need matplotlib for plots in examples.

rgommers/pywt,rgommers/pywt,grlee77/pywt,PyWavelets/pywt,grlee77/pywt,rgommers/pywt,rgommers/pywt,PyWavelets/pywt