adding todo item for runner testing in future
Added test for page_load (integration only as we cannot sandbox calls involving phantomjs) + test fixtures for same.  Small modifications in page_load.js for usability and coherancy.
minimal modifications to tests for runner as changed behavior for invalid JSON returned from callback inside page_load & changed page_load to accept non-truthy but defined (valid JSON, e.g. false) returns from callback and reject undefined or similar returns
minor notes added to runner_test