better handling when requested "hilite nodes" not found (in whole or part)

[adf-ncgr]

currently, the logic is just to put "jump to" links in for every label included in the query param. However, in many cases, the desired target label (or a subset of the desired target labels) will not be a node in the tree (e.g. for genes in legumeinfo that we have assigned to families but not added to the trees). This can be confusing for users (e.g. Amanda cited this when doing her initial assessments of general site usability). It would probably be relatively easy to sequester the subset of labels not present in the tree and either suppress them altogether or put them in a "not found" message; even better would be to get whatever labels aren't found in the tree but are found as features in the db and offer to lorax them in for the user. This might be a better alternative than how I had previously imagined similar functionality being triggered from the GCV, since it would be more broadly applicable (e.g. coming in from gene page links) and probably easier to implement as well.