Changed and added mlg.group to mlg
re-roxygenized
modified mlg.group tests
Created function update_edge_scales
implemented update_edge_scales in msn functions

poppr.msn, bruvo.msn, singlepop_msn, and plot_poppr_msn were all modified to use this function.
updated plot_poppr_msn man page and NEWS
Removed unnecessary comments
update
changed mlg.group to mlg.id

This seemed to make the function's purpose clearer.
make sure tests work
updated mlg documentation.
updated poppr man page.
modified figure
added mlg.id to vignette
fixed typos [ci skip]
Started work on proofreading documentation.
changed back default percent to "FALSE"
fixed R CMD check
Add catch for negative or NA cutoff plot_poppr_msn
Changed diss.dist default percent = FALSE