Stop using the default processor in the specs

We're going to expose Processor as more of a public object, so it makes
sense to use it as such in the specs
Use JRuby's rubyised method names
Allow configuration file to be passed in

This tackles the main part of @papile's #1.

The test for this is messy because it's unclear to me whether the
configuration object is something that should be manipulated after the
processor has been created. Feedback from @michaelhkay @ond1 or @papile
appreciated on that one.
Merge pull request #3 from fidothe/expose-processor-config

Expose processor config