export/import of skin doesn't record creator name / creation date

[Robert Lyon]

Currently with skins one can export a skin allowing others to import the skin but the skin creator and creation time of the skin is not added to the export.
These two pieces of information need to be added to the xml file that is generated.

Also, there is no facility for the imported skin to record the creator of skin.

There needs to be a new char column in the skin table that records the name of the originator from skin import and on import set the ctime to the ctime listed in the xml file.