Passing test for signed in user

This fixes it, tried directly finding the element and using webdrivers
text method first but this has the same incorrect idea about the dom.
Not found anything obvious about this issue in phantom 1.9.7 and don't
want to spend too long so using this hack for now. These tests may
become defunct soon anyway.
Change the matcher on 'message' to require exact matches [#72627064]

- Previously we've been doing a regex match that didn't need to match the message field exactly
- This meant changes to error messages were only being partially matched/partially tested
Pass back data-set name to write and create api methods [#72627064]
Fix tests [#72627064]

- Tests now expect the presence of a data-set name
Add in a specific test for parse errors

- Different environments (e.g. Travis) will throw different types of parse error, so having an exact match isn't desirable/going to pass.
- However, we don't want to lose the exact matchers on other messages, as they are useful tests
Move response from read to core