Add the ability to change which tag contains a piece of content

[prototype27]

Please add the ability to change which tag refers to a piece of content. For example, if a file has "foo" in an Artist tag, I want to be able to change it so that "foo" is in a Title tag instead, etc. Thanks!

[Mathias Brodala (mathbr)]

This basically means moving the value from one tag to another which is something the user can do the best by just editing the tags. There seems very little gain in adding some complicated system to handle this internally.