don´t show negative numbers. this is only a quickfix. I still dont get why the Shared folder can be bigger than the root folder. Perhaps a inconsitency in the filecache?

CSS typo fixed.

Added failsafes for retrieving remote apps on settings->apps page, in case categories or app data are not found

Added method getAppstoreApps to OC_App
Added minor documentation

every translation within the sub folder 'settings' need to use 'settings' on OC_L10N::get