slick/slick — pull request #793 by szeiger (2014-05-02 15:51:10+00:00)
Title: Support Unit values in Query return types.

- Emit a dummy value ("select 1 from ...") in
JdbcStatementBuilderComponent for a query which returns an empty
ProductNode or StructNode.

- Add a UnitResultConverter of width 0 and create this instead of a
ProductResultConverter for empty ProductNodes.

- Return classTag[Unit] for arity 0 in TupleSupport.classTagForArity.

Tests in RelationalTypeTest.testUnit. Fixes issue #742. Review by @cvogt.