Update to v0.64.0

[Chris Watson]

Hello, I have made an update to v0.64.0.

There was an error in some situations when returning permutation p-values by the function "SPM". This has been corrected.

"plot_rich_norm" should now work for more than 2 groups. It will also work with multi-subject data; it collapses across "Study.ID" and plots the group means

You can see the changes on the Github page.

Chris