SNU lookup rules should be associated with link widgets

[sthiel]

by default, this can be all available link widgets for the interface (see #143).

Further clarification (hopefully): This ticket represents that one should be able to identify, via id (in the xml), which link widgets are associated with a given next snu lookup. You could have 10 link widgets across your interface, and at t=5s, three of them show results for one lookup rule. At t=14s, perhaps the other unused 7 will show the results for the next lookup. The ordering of the widgets in the rule association should be the order from highest/lowest that results are given in, but it's okay if this gets defaulted to #1/#2/#3.