Roxy design enhancements

Design enhancements

This is a doc to hold design enhancements for a future Roxy version

• add the ability to conditionally use bits of ml-config.xml Something like:

<database if="@ml.environment = ('dev', 'prod')">
...
</database>

This database would only be created in dev and prod

• Add the ability to include other xml files. This lets us split up long ml-config.xml files and re-use bits from other files.

• Enhance our ability to reference other configs. We allow you to reference another database or appserver. Extend this to anything.

• Do a final check to make sure there are no dangling @ml.whatevers defined. Heck, we might already do this. But warn the user and stop

• Perhaps do a static check of the xml config before attempting to exec it. This would catch any malformed xml errors.