Incorporated the ability to express XML attributes with our configuration

Most plugins don't have xml attrs, but the antrun does. This patch provides support for the configuration with attributes by permitting the following syntax:

Config(`@myAttr` = "someattrval")

i.e. attributes are prefixed with an "@".

I'm not entirely happy with this syntax for specifying attributes - it is a bit cumbersome. However it does work and can get us over the hurdle.

This PR also includes some code cleanups.