Allow image thumbnails to be disabled
Remove signature hook

The same thing can be accomplished via preference hooks
DIMP -> Dynamic
Merge branch 'master' into imp_6_1
[mms] Dynamically display MIME type icon for attachments uploaded on the dynamic compose page.
[jan] Move shared ruleset selection to sidebar.
Expand documentation on shares.
Hide shares of gone backends.
Turn transport factory into a base factory.
Fix class layout.
Merge toCode() methods into generate().
Remove globals usage from Ingo_Script, inject dependencies instead.
Merge branch 'master' into imp_6_1
Fix parsing msgload parameter
[mms] Save AJAX showMessage call when reloading the dynamic mailbox page with a message preview active.
Fix pre-buffering of unseen messages in dynamic view
Make sure there are not duplicate Ids
Fix selecting messages in mailbox view
Get rid of IMP_Ui_Folders

Move import/generate code out of IMP_Ui_Folders/IMP_Mailbox and into its
own separate IMP_Mbox_* classes.
IMP_Ui_Imageview -> IMP_Images