revert the context_return change to is_many accessors

The context_return assertion (#17, 67f5281) broke a couple tests in Workflow
and, maybe just indirectly, a couple hundred tests in Genome.
convert test to use subtests
Merge pull request #37 from nnutter/master
Fix for older versions of SQLite

Use the shim method call to get table information instead of the direct DBI
call.  Older versions if SQLite return NULL for schema.  Newer versions can
return 'main'.

Change-Id: I5772ad0fd0e59468d3dd18990a394eb702bba412
Merge pull request #38 from amb43790/perl5.8-fix