Importing CSV file with no headers does not allow for importing Column 0 - Patch Included

Creating an importer for a content import for a client. The supplied CSV file(s) include no column headers so I am using the "No Headers" option on import. However, when creating the mappings I am unable to map column 0 (as the file parses to a 0-based array) to a field. This is significant as there is valid data in column 0 and it does not work to modify the file(s) to add an empty column.

I have attached a patch which modifies the feeds_ui_mapping_form_validate and feeds_ui_mapping_form_submit to explicitly check if the submitted value is '0' as the current implementation of empty($form_state['values']['source']) evaluates to TRUE when 0 is submitted which thereby prevents mapping column 0 to any field(s).

I've tested this patch for my files when using the import with no headers option and it works successfully.