Fix capitalization of 'BOF' in parameters

[tobiasdiez]

The file is called st_scrap_in_BOF_rate.cs4r with a capital BOF, which lead to errors as it couldn't be found (perhaps a linux/windows issue).

Thus used the capitalized version everywhere (where I could find scrap_in_bof_rate). The alternative would be renaming the file to lower case.

[JakobBD]

Interesting that Windows seems to be case insensitive when looking for files?

I'd prefer to change the file name (no good reason for capitalization here). But it requires to have the R packages set up.

If you want to merge it now to have a working version, I'm fine with it!
We can revert the commits once we changed mrmrfa (probably never :-D )

[tobiasdiez]

Proper fix is at pik-piam/mrmfa#64