formatting
recenter test client on default graph origin and add new graph inspector layers
Add generic distribution stats class.
More complete graph statistics. Use generic stats.
Remove --graphStatistics option, not really useful.
Merge pull request #1494 from laurentg/graph-stats

Graph statistics
Add config file Preferences implementation

This config file format was proposed on mailing list:
https://groups.google.com/d/msg/opentripplanner-dev/tk427ITino0/NARvCmyfKPoJ
More tests for invalid config file input.