Replace HttpRequest toString() with an equivalent HttpRequest.toJSON()
Replace HttpResponse toString() with an equivalent HttpRequest.toJSON
Replace http error messages with json-stringified versions of the errors
Add a pretty printing util
Add serializing and pretty printing of http fixtures
Allow non-existant keys to be given for prioritising in pretty printing util
Pretty print http errors
Better pretty printing util
Add an indent util
Change http errors to work with the pretty printing util changes
Fix mixed indentation
Minor improvement to http error output
Merge branch 'develop' into feature/issue-195-less-ugly-fixture-error-output
Merge branch 'feature/issue-195-less-ugly-fixture-error-output' into develop