Report user about refresh errors in the list of files

[tobiasKaminsky]

trafficstars

If the app cannot load a folder content list, it should check webdav according to https://github.com/owncloud/android/wiki#data-is-not-shown-after-haved-login and inform the user that there is a problem with webdav and not only show "nothing here".

Even better: handle more common problems, like out of time, no connection, no ping...

[LukeOwlclaw]

I like the idea to handle all these errors in a common way. Then this issue is somewhat related to https://github.com/owncloud/android/issues/162

[davivel]

Let me rephrase the title.

[jesmrec]

Error handling, show error as in other operations.