Pairwise PERMANOVA

[raivo-otus]

I understand that the addPermanova() and getPermanova() functions perform global PERMANOVA.
However I can't seem to find an option to do Pairwise PERMANOVA within mia on TSE objects.

It is only a small inconvenience to pull out the distance matrix and grouping metadata to preform pairwise PERMANOVA.
Having it as an option in the mia functions or perhaps a separate addPairwisePermanova() would be convenient for the user. This feature would be a nice addition to further inspect significant results from the global PERMANOVA.

[TuomasBorman]

Thank you for this great idea! In theory, this should be relatively simple to implement by using the existing functionality. Does @antagomir has thoughts on this?

[antagomir]

For sure let's add.

[TuomasBorman]

Issue in mia: microbiome/mia#734