rspec_rabl

Adding an original jruby target for CI (which is passing)

Adjusting CI targets to (hopefully) allow for installation of dependencies (specifically activesupport (5.0.0.1)

Adding ability to specify Rabl::Renderer scope for an example group to, for example, allow Rails view helpers to be called from rabl templates within a spec

release 2.0.0

Merge pull request #19 from ztoolson/zt/nil_value_check