better error message, closes #138

Conflicts:
	redaxo/include/addons/image_manager
fixed #140

Conflicts:
	redaxo/include/addons/image_manager
updated lastchanges

Conflicts:
	redaxo/include/addons/image_manager
fixed export name

Conflicts:
	redaxo/include/addons/image_manager
import_export: Fehlende Ordner werden automatisch ergänzt. createFolder func ergänzt

Conflicts:
	redaxo/include/addons/image_manager
added system files, closes #142
avoid empty accesskeys

Conflicts:
	redaxo/include/addons/image_manager
mpool: delete multiple files: better success message

Conflicts:
	redaxo/include/addons/image_manager
added missing lang key

Conflicts:
	redaxo/include/addons/image_manager
rex_select: improved optgroup handling, closes #145

Conflicts:
	redaxo/include/addons/image_manager
use htmlspecialchars() for optgroup labels

Conflicts:
	redaxo/include/addons/image_manager
bugfix: inherit template of start article

Conflicts:
	redaxo/include/addons/image_manager
better label for SERVER and SERVERNAME, closes #148

Conflicts:
	redaxo/include/addons/image_manager
phpmailer: changed default mailer to "mail", closes #147

Conflicts:
	redaxo/include/addons/image_manager
initialize rex_select properties, avoids warnings

Conflicts:
	redaxo/include/addons/image_manager
better file sort, refs #140

Conflicts:
	redaxo/include/addons/image_manager
updated lastchanges

Conflicts:
	redaxo/include/addons/image_manager
version addon: fixed links, closes #155

Conflicts:
	redaxo/include/addons/image_manager