Ignore pycache everywhere
    
    With the introduction of a bin/lib/ subdirectory containing Python
    files, __pycache__ directories are now contained in nested places
    as well, and it makes sense to expand the pattern to exclude any
    __pycache__ directory anywhere.
    
    Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>