Harmonising the functions with `mplot`

[kevinwang09]

One attempt is made here with the mplot_boot function, though it is merely a wrapper to convert the results of APES into mplot.

https://kevinwang09.github.io/APES/reference/mplot_boot.html
https://github.com/kevinwang09/APES/blob/master/R/mplot_apes.R

[kevinwang09]

FYI, @garthtarr, I already got started on this. Though we can think about deeper integrations of the two packages if needed.