Mixing matrix with different ego and alter attributes (unipartite and bipartite).

[krivit]

The rows' grouping of a mixing matrix does not have to be the same as the columns' grouping: one can, for example, count number of ties between Male students and students in 7th Grade. From the UI point of view, it could be as simple as letting attrname be a character vector of length 2.

[mbojan]

I'll be happy to do that. Something along these https://github.com/mbojan/isnar/blob/master/R/mixingm.R lines perhaps?