Sanitize displayname, respect data @ $element, fix routename, clean after cropping, updateAvatar with displayname

Rather display a dominant div and mark the problematic app in the applist.

Fix #305

Useful and prettier

add a check and a warning if the ownClodu server is not able to establish http connections to the internet. The reason is that users complained that external filesystem support, the update checker, downloading of new apps or the nowledgebase don´t work and don´t know why.

CSS typo fixed.

Remove sharing notice in users settings - The default is now share with anyone, groups only sharing is now a setting in the admin page