add Look and Feel changer utility class
Resource: add constructor with classname

if the resource file is named like the class, this removes the need to
hardcode the package+class name into the Resource constructor call
move i18n files to the same package as the class they belong to
add possible TODO (recheck this!)
add i18n to ColorBinding and FileBinding

- i18n tooltips for "..."-buttons
- i18n for dialog titles
- i18n for selection button in FileChooser