Pangolin SRX web editor

(proposed rename to Ground Pangolin as there are several projects named Pangolin)

This is an early implementation of a web-based SRX editor application based on
libraries from the Okapi Framework (http://okapi.opentag.com/). The application
is modeled after Ratel (http://okapi.opentag.com/applications.html#Ratel), with
extensions to load and save documents from a number of sources.

More information on the SRX document format and purpose can be found through the
Okapi website: http://okapi.opentag.com/standards.html#srx