Derby embedded in Geronimo

[Jeremy Boynes]

For those interested, I have begun a simple embedding of Derby into 
Geronimo allowing it to act as the SystemDatabase for functions such as 
persistent timers etc. It is also generally bound as a local-transaction 
resource for use by applications.

If things work out well and there are no objections I plan to switch 
away from Axion as our default embedded database.

Before then, there are a couple of things that need to be done if anyone 
is interested in participating:
* GBean wrapper for NetworkServiceControl
* verification of XA support and recovery
* switch connector to use DataSource internally rather than
  the DriverManager
* expose database properties to JMX via GBean wrapper
* operations to create/delete databases & other adminy things

I'll add these to the Geronimo Jira as enhancements.
Thanks to the Derby team for giving us the chance to use it.
--
Jeremy