UX: Improve adding/updating avatars and other attachments

[arborrow]

It would be nice to have drag and drop functionality for attaching files. I envision an attachments box where a user could simply drag and drop the file. Currently there is no way through the UI to edit the description of an attachment. Another place where this drag and drop functionality could be beneficial is with the user avatars or pictures. The goal is to eliminate all of the clicks required to go into edit mode, click on the add picture button, find the picture and upload it and simply be able to (if the user as the update-contact privilege) drag the image into the picture/avatar area and it would be uploaded automagically.