Convert center points to edges.
Examples
>>> x = [0., 0.1, 0.2, 0.3]
>>> y = [20, 30, 40]
>>> centers_to_edges(x, y)
[array([-0.05, 0.05, 0.15, 0.25, 0.35]), array([15., 25., 35., 45.])]
mne.viz.centers_to_edges
#Time-frequency on simulated data (Multitaper vs. Morlet vs. Stockwell)