Reinserted icon and link for preview of agenda slide. Fixed #1199.
Merge pull request #1211 from normanjaeckel/PreviewAgenda

Reinserted icon and link for preview of agenda slide. Fixed #1199.
Merge remote-tracking branch 'openslides/stable/1.5.x'

Conflicts:
	extras/win32-portable/create_portable.txt
	extras/win32-portable/prepare_portable.py
	openslides/motion/templates/motion/motion_list.html
	openslides/projector/templates/projector.html
	requirements_production.txt
Added global chatbox for managers.
Improved chatbox style. Updated jquery cookie and jquery ui.