Shorten the (very) long author lists

[Randl]

For a very long author lists, the common solutions are either print all the names or only the first couple of authors. For personal website both are not very suitable.

I suggest adding an option to config with maximal number of authors. If the number exceed this number, the author list would look like
A, B, C and 15 others including self (where self is usual self for the publication page).

[rohandebsarkar]

PR #732