Editor: Adjust name/path of edited content files
When the editor loads a content file, it potentially can not save it back to the same location and with the same name.
a) The content file may be located in any data directory, but we only have write access to --data-local.
b) We can not write .esm and .esp files, so the extension must be changed when editing legacy format files.
The editor should make the required changes automatically and the user should be informed about these changes, when loading a file (including information about the new name).
(RM-588 from redmine: created on 2013-02-24 by Marc Zinnschlag, , closed on 2013-09-10 by Marc Zinnschlag)