Treat all ggo files as m4 files. Most input files for gengetopt are already generated from corresponding m4 files. This renames the remaining ones, so that all .ggo files are now generated and can be removed by the make clean variants. Hence we do not need to track the set of generated ggo files any more.
Revamp para_fade. - Rename options - Improve documentation - Make --mode an enum option - Cleanup ggo file indentation
Teach para_fade to accept a mixer channel to fade. This allows to fade not only the volume channel but all other channels that are supported by oss.
Move ggo files to a separate directory.