allow one column data-table to be passed as parameter
Improvements around PR "allow one column data-table to be passed as parameter"

- added/renamed tests, added comments
Merge branch 'pr/48' into groovy-1.8
Add shippable config
Improve build configuration for shippable CI
Refine Shippable CI config
Run Shippable CI build against a single JDK only
Merge branch 'groovy-1.8' into groovy-1.9
Run 2.0 branch against OpenJDK7 on Shippable