Extend and synchronize redcap backends

Remove order (because it is an internal value by which the fields should
be sorted, which they are, but it is not exposed through the api or csv
export) and units (because it is deprecated) from the redcap_mysql
backend and add display_logic, header, alignment, survey_num, and matrix
to all three redcap backends (api, csv, mysql).
Merge pull request #14 from aaron0browne/master

Extend and synchronize redcap backends fixes #13