A replacement for LinkedList/Vector for use in maintaining lists of
related LinkLabelAddresses that saves space by only actually using
a hash table if N is more than 1.
Handle the link operator, which is used to query for all direct
links to or from a node (NOT to assign a link or test for a
particular relationship, which are handled by = and ==/=~
respectively).
Super-duper-easy constructor that takes a string,
assumes it is a free-text comment, and sets up a single
"comment" attribute for the label with the parameter