Use LooseVersion for checking cython version (issue 298)
Add errors table entry for bad references
Add test for ValueError in response to invalid ref (issue 294)
Merge pull request #313 from andrewcollette/issue_298

Use LooseVersion for checking cython version (issue 298)
Merge pull request #314 from andrewcollette/issue_294

Issue 294 (ValueError in response to invalid reference)
Fix non-bytes literal in h5ds which breaks in newer versions of Cython