Maxima Function
killcontext (context_1, ..., context_n)
Kills the contexts context_1, ..., context_n.
If one of the contexts is the current context, the new current
context will become the first available subcontext of the current
context which has not been killed. If the first available unkilled
context is global then initial is used instead. If the initial
context is killed, a new, empty initial context is created.
killcontext refuses to kill a context which is
currently active, either because it is a subcontext of the current
context, or by use of the function activate.
killcontext evaluates its arguments.
killcontext returns done.