Author search by name

[Juma7C9]

Hi,
I expanded the search function allowing to use the author name as a filter, other than their ID.
As the infrastructure to do so is already largely in place, the only change is to split the author list and check each token to see if it is numeric or not, and recreate two lists - one for author IDs and one for author names.

This way inside the shortcodes is possible to specify any combination of author=1,3,42, author=J. Smith,Jane Doe, or author=1,Jane Doe,42, and the search will return all the publication that matches at least one of them (with partial matches for author names, as they are passed to a LIKE %name% clause).

This change is mostly backwards compatible, as lists of numeric author IDs in shortcodes are processed the same as before, while the functions TP_Authors::get_authors() and TP_Publications::get_publications() now return entries that matches at least one of those passed in author and author_id instead of both of them - but I'm not sure if is was ever possible to specify both using publicly available functions.