Add parameter for import-roms to Trash the files that are being imported and are duplicate of what has been already imported

[lemonadecbc]

It would be great enhancement to allow deleting of roms that are being imported if those are duplicate to already imported roms. This should naturally not be default way to handle importing roms, but would be nice additional feature to make it easier to remove the duplicate files while importing roms to collection.

[alucryd]

Agreed, the trash flag already exists, I'll extend its scope to duplicates.