Izug.ticketbox

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- Fix answerdate in ticket response
It was not possible to set a answerdate in the response of a ticket.
Neither through manual input nor calendar widget.
[elioschmutz]

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- Fix display failure when adding a comment in a notificationform.
[elioschmutz]

- Add upgrade step for the icons of the ticket and ticket box types (the icons
have been moved to a resources directory).
[mbaechtold]

- Fix ticket attachment type icon.
[jone]

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- Remove unnecessary viewletmanager from template since it leads to duplicate Bylines.
[tschanzt]

- Use ftw.calendarwidget on responseform.
[tschanzt]

- Hide unused files in Ticketview.
[tschanzt]

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- No longer recycle Description as TextField.
This lead into problems with tinymce (Somehow).
[mathias.leimgruber]

- Export ticketboxes as a ZIP file with the help of ftw.zipexport:

- XLSX file containing data from all tickets
- attachments of all tickets in separate folders

[mbaechtold]

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- Export the tickets to a XLSX file.
[mbaechtold]

- Show the title of the ticketbox on the overview tab.
[mbaechtold]

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- Hide description on ticket_view.
[tschanzt]

- Reenable document_actions on ticket_view.
[tschanzt]