New 'who'

Though it may not be obvious, the 'who' command has been substantially overhauled to handle arguments (and argument mixes) much better, and operate more quickly. It will now handle added arguments for paths and last names (which we will introduce shortly) as well.

Many thanks to Bhuta for the overhauled function itself, and to Altrag for his own updates and plenty of tweaking and work to get it fully functional within our code base.