Fix #19 (NPE when importing project into Eclipse/Maven) for third time
(@paulcwatts fixed in pull request #49 as well).  @sheldonabrown - it
seems this keeps getting overwritten in the release process.
Merge pull request #68 from Hillsborough-Transit-Authority/fixMavenNPE

Fix #19 (NPE when importing project into Eclipse/Maven) for third time
Return a human-readable error message rather than an exception when GTFS-realtime export fails.
Prevent exception when rendering GTFS-realtime alerts which lack time window or affected entities.
Merge pull request #71 from kurtraschke/gtfs-rt-export-fixes

GTFS-realtime export fixes