Adds failing test for issue #351
Fixes issue #351, where the reordering of list-items was not reflected in the DOM.
Update changelog and contributors
Try to work around travis having problems with Drag & Drop
Merge pull request #356 from collective/issue_351

Fixes Drag&drop list sorting not being updated correctly on the first try
Add warning message about deprecated Image and Link tiles (refs. #218)
Define logger only once in upgrades.

The steps are only called with a logger argument when you call them from your own code,
for example an import step that passes the portal and the logger to these functions.
But that does not happen in our code.
Add test for upgrade from 6 to 7.
Make upgrade step title nicer.

No underscores needed here.
Use own permission for layoutedit tab.

Permission is: 'collective.cover: Can Edit Layout'
Upgrade: only set layoutedit permission.

This is nicer in case someone has changed the cover type in his site.
Fix layoutedit tests.
Merge pull request #359 from collective/maurits-layoutedit-permission

Use own permission for layoutedit tab
Add La Jornada to the list of sites using collective.cover