Basic changes
Some fixes
Added more tests
Fix tile carousel custom url robot test
Fix tile list robot test
Tentativa de correção dos testes RF (bug após inserir mais imagens)
Fixed tests RF
Added robot tests for custom title and custom description
Update changelog
Update docstrings
Do not pass silently as we have a bug over here

@frapell this has to do with the implementation done in #451.

To replicate:

* add a carousel tile to a cover
* drop an item to it
* edit the tile to add a custom URL to the item
* edit the tile again and remove the custom URL
* drop another item into the tile

the first item is replaced by the second.

it would be great if you have time to check this and point us where the problem is; @rodfersou will work to fix it.
Merge branch 'master' into issue_459
Merge branch 'master' into issue_459
Some fixes in the test
Merge branch 'issue_459' of github.com:collective/collective.cover into issue_459
Fix tests
Merge pull request #460 from collective/issue_459

Allow to choose custom title and description in carousel tile