*** Users ***

There are a number of things which apply to user objects that do no apply
to other object types and I will list them here.

int (*misc_func)() - This is a function pointer that is checked and if not
   NULL is called without calling exc_com. This is done so that the normal
   mud command shell can be bypassed with an alternative one.

skill structure - This stores any learned skills in the form of the skill name
   and a function pointer to the function that runs the skill. exec_com()
   tries to match any user input with any skills that may exist.

event functions - These apply to users as much as they do other objects.
