This function deletes a previously defined deftemplate.
Syntax
(undeftemplate <deftemplate-name>)
If the deftemplate is in use (for example by a fact or a rule),
then the deletion will fail. Otherwise, no further uses of the
deleted deftemplate are permitted (unless redefined). If the symbol
* is used for <deftemplate-name>, then all deftemplates will
be deleted (unless there is a deftemplate named *). This function
has no return value.