Widget to customize popup behaviour.

• change size of popup
• show attachments as thumbnails or icons. -> 4 themes - default : just add the size of the file - icon : add the size of the file and show an icon before the filename. This icon can be an extension icon (xls, pdf....) or an image overview if the attachment is a small image. - thumb : thumbs of attachments (70px * 70px per attachment) with an image overview if the attachment is smallest image than defined in the config. - large : each attachment is displayed as a large thumb.