select_navpoint("") sometimes crashes.

[GoogleCodeExporter]

What steps will reproduce the problem?
 1. Call select_navpoint with an empty string as the only argument.
 2. Sometimes, the empty string isn't in navPoints so an Exception is raised on line 105.

What is the expected output? What do you see instead?
 If navPoints doesn't contain the empty string, return false instead.

I fixed it in my local copy by replacing line 100 with the following:
if (__closestNavpointID__ == null || 
!navPoints.ContainsKey(__closestNavpointID__))

Original issue reported on code.google.com by [email protected] on 3 Apr 2014 at 11:09