Inline Editing Attachments / SharePoint-like functionality

As a JIRA user, it would be really helpful to edit attachments on the fly.

Current scenario:

To edit an attachment in JIRA, an user needs to manually download the attachment. Then edit what is needed, save, and upload a new attachment (and then remove the old one if necessary).

Suggestion:

1. When the user clicks a link to a document it downloads it and opens it (Word/Excel etc);
2. The document is locked for concurrent editing;
3. When the document is closed, JIRA checks if it has been edited, and if so displays a box asking if you wish to upload the change and write a comment.

Notes:

A similar thing can be achieved in Confluence with the GoEdit add-on. This is also tracked for Confluence on CONF-5932.