Adds test Travis-CI support for Cascalog-LZO

Fixes #129. About a year ago, the Travis-CI build failed due to a lack of native LZO libraries on the CI machine; this has since been fixed, and now the Travis-CI build passes. See my [fork](https://travis-ci.org/timbers/cascalog) for proof. 

As the Travis-CI build (currently) passes when Cascalog-LZO is added to project.clj, it should be added to project.clj in the main repo to guarantee test coverage.