Allow redoing OCR with other language and "deskew" off per document

[igno2k]

My default language is german and I use that for all documents. But some documents are english and it would be good to redo OCR for this documents by changing the language after reviewing the document.
I know you can set more than one language in the options but this uses a lot of CPU. Therefore I think it is better to change the language afterwards.

I also have a lot of digital documents (like newspapers and magazines) that get wrongly "deskewed" by ocrmypdf. It would be nice to redo OCR also for single documents with deskew=false.