(#471) - Test bulkDocs errors

Add a test for the bulk docs error inconsitency.
(#471) - Test bulkDocs multiple errors

When there are many docs with invalid ids, only the first error should
be reported.
(#471) - bulkDocs errors inconsistency

Return with the first error when some documents have invalid ids.
Merge pull request #473 from daleharvey/471-bulkDocs-errors

471 bulk docs errors