Dumpgenerator also save a logfile

[robkam]

Please add an option so that dumpgenerator messages can be saved to file as well as the terminal.

[robkam]

Done with #56

[robkam]

The log should be written into the same folder as the dump(s).

Please could it filter out what it's going to do and only log what it has done? So that it more resembles what's in the terminal. Lines like these aren't useful:

    .
    ..
    ...
    ....
    .....
                           
    Retrieving titles in the namespace 3