Add debug page to TDS for displaying bounding box and WKT for the current bundle's geographic coverage.

When setting up the OBA webapps, it is necessary to have the current bundle's geographic coverage, and, for OBANYC, a WKT polygon for filtering geocoder results.

Service area can be computed automatically, [except](https://groups.google.com/d/msg/onebusaway-developers/1Ip_zu_atjg/WBRSXAGTTS0J) when the UI webapp is running in the same container as the TDS.  These values can also be found with [an external script](https://gist.github.com/kurtraschke/4323377), but that is a nuisance.

This pull request implements a debug page in the TDS which displays the bounding box values and filter WKT, easing deployments of the webapps.