Adding ability to import incrementally + miscellaneous corrections
- jira-import-export : detection of attachments already imported
- Template_Change_GT44_to_Jira_GT44.xlsm : adding, in imp_attachments sheet, extraction of Filename from AttachmentPath to ease the detection by jira-import-export script of already imported attachments
- Template_Change_GT44_to_Jira_GT44.xlsm : minor corrections (typo, ...)