added a function to swap the minor edges of an evonet object

[jjustison]

Here is a function that swaps what the evnoet object considers the minor branch. It swaps the hybrid edges of a given hybrid node from net$edge to net$reticulation. This might come in handy for folks that want a bit more customization for their plots

[KlausVigo]

Dear @jjustison,

thanks for the pull request. Sorry, that it took me some time to review this.
I created a development branch (devel). Can you make the pull request into this branch, I want to try to keep the master branch clean.
The package is accepted in bioconductor and I did not want to make any API changes before the next release on Wednesday.

Just some other tiny changes.
Can you please add the line
#' @importFrom ape node.depth.edgelength
just before #' export in line 15.

Feel free to add yourself as an author to the DESCRIPTION file.

Thanks again,
Klaus

[jjustison]

Ope, sorry to muddy the master branch before release. Made the changes as requested.
Also, thanks for fixing those issues from earlier, it helped a lot!