ZoteroRequest now flattens creator fields

Added .json file with sample Zotero response for faster testing.

Added modifyBody method to zotero.js to alter the response.

Currently removes creator field and replaces it with flattened
fields that citation templates could take, such as editor1-first for
the first name of an editor. Note that there is currently no
citation template that takes author1-last directly; equivalent fields
on en.Wikipedia, for example, might be last1, author1, last, etc.
Because each wiki's citation templates are different,
fields would have to be assigned to their equivalent field in
TemplateData to be used.

Change-Id: I17b161dad696a9f6e4346b7fc89736c9d6aeae84