Moved config file location constants to their own file to not repeat
myself. I originally wanted to move the file reading and writing code
there too. However, the usages in the two files are sufficiently
different to make refactoring nontrivial. Since I don't expect this
part of the code to become part of the library, I decided it wasn't
worth the effort. But having the constants in one place was worth it
since there may be a reason to change them in the future (like
executable name changes, for example).

I also split a number of long lines in make_fogzap_pickle.py to
improve readability.