DW: returns a json response on error
DW: Added a check for a template before report generation, updated the documentation on xls reports, updated and added tests
DW: Concatinating string using format instead of using +
Merge pull request #694 from onaio/690_return_json_object_in_xls_report

Checks for a external export template
DW: Added version to xform and instance. Overide the default partial update to replace a form
DW: Corrected failing tests
DW: Added test for a bad xls file update. added version param in data export and code refactor
DW: Code refactor
DW: Added more tests, removed the seconds in the version, code refactor
DW: Code refactor
DW: Corrected failing tests
DW: Added version column to the exports
DW: Corrected failling test
DW: updated the sav export fixtures