Write `process.log` in the same directory as the input file

[timothy-nunn]

The process.log file is written in the current working directory. It would be useful to write this log with the input file and maybe even name the log in accordance with the input file. E.g. MY.IN.DAT produces MY.process.log.

@jonmaddock

[jonmaddock]

Thanks for creating this from my ramblings Tim.