userlog rte update alerts: good rtes + bad labels

[yakra]

Some additions to userlog route update alerts per #189 (comment)

• 4-field lines
  • label(s) not found
  • duplicate label
  • same-point AltLabels (zero-distance)
• 6-field lines
  • not in same connected route
    (assumes routes were previously connected; reports start/end of ConRte)
  • same-point AltLabels (zero-distance)

Alerts for some 6-field error types are not yet implemented:

• Waypoint label... not found and duplicate label are the most sensible, and their 4-field counterparts are implemented. These are postponed pending a potential reorganization of that part of the code.
• Reports for Unknown region/highway combo might be going a bit overboard...

Don't know what the merge conflict is all about. I'll see what I can see.