Yikes a bug!

Found a bug in the lists library. When a node is unlinked from a list its next pointer was not reset to NULL. Typically not a porblem because up until now this was always a node that was being deleted. Now we have nodes that swap from one list to another and the NULL pointer is needed as a flag.

Also added a method to linkList, looseList(). This can be called to have the link list "give up" its list and reset its list to NULL. Of course if no one takes over this list you just created a giant memory leak. So be careful with this call.