Describe the problem

Currently there is no easy way to directly visualize Annotations. I always have to convert them to events first and then use mne.viz.plot_events(), which seems pretty awkward.

Describe your solution

Similarly to mne.viz.plot_events(), there should be mne.viz.plot_annotations() and Annotations.plot(). They would require the user to pass an info structure, and otherwise work similarly to plot_events().