Update popover allow htl content

Popover is displayed with escaped html tags.
Fix XML support
Fix array_diff comparing nested arrays
Merge pull request #1457 from marekkalnik/fix-extension-filtering

Fix array_diff comparing nested arrays
Merge pull request #1456 from WouterJ/fix_xml

Fix XML support
Merge pull request #1455 from dkorsak/patch-3

Update popover - allow html content
Merge branch 'sonata/master'