Initial implementation of the Oracle Provider

Hey, 

Initial implementation of the oracle provider.

Some things to note. 

* I have changed how SqlRuntime.QueryExpression presents the Linq args (basically removes the prefixed _), I have tested against a simple oracle, sql server and sql lite db, but only very quickly. If this breaks stuff I'm sorry, send me a note and I'll fix it.

* Added an extra static parameter owner, as by default GetSchema gives you everything for oracle and this would pollute the type space with crap loads of system tables and other fud. 

* You can run sprocs but functions are not supported yet, I'm not really sure how to handle this. The same goes for mutliple return sets. 

* Added a tests assembly so at least we can dump scripts that we know work somewhere, testing this provider across all db's is going to be an interesting thing to achieve :s.