merge master into filesytem

apps/files/ajax/autocomplete.php

apps/files/ajax/delete.php

apps/files/ajax/getstoragestats.php

apps/files/ajax/upload.php

apps/files/index.php

apps/files/js/files.js

apps/files/js/jquery-visibility.js

apps/files/l10n/ar.php

apps/files/l10n/bg_BG.php

apps/files/l10n/bn_BD.php

apps/files/l10n/ca.php

apps/files/l10n/cs_CZ.php

apps/files/l10n/da.php

apps/files/l10n/de.php

apps/files/l10n/de_DE.php

apps/files/l10n/el.php

apps/files/l10n/eo.php

apps/files/l10n/es.php

apps/files/l10n/es_AR.php

apps/files/l10n/et_EE.php