Allow more complex configuration of vendor properties in the RuleContext annotation

[dabdine]

The vendorProps annotation attribute is insufficient for cases such as drools right now, as drools will look at the vendor props for key/value pairs where the values can be complex java objects (such as readers for the DSL, etc.).

See: http://docs.jboss.org/drools/release/5.2.0.Final/drools-expert-docs/html/ch07.html

We will need a programmatic approach to supply property values.