external tools for dealing with Patel's temporary input format (which I'm
 calling "Patel Packet Format" or 'PPF')
NB: These are what I planned, but only notestoppf.pl was made before the
 first release. The rest should be made for the second release.


muxpatel: reads in set of PPF files each defining one channel, writes out all
 channels multiplexed into one PPF to standard output. Fails if any input
 file describes more than one channel. Channels of output are numbered
 according to the order in which input files are specified (IE: first file
 becomes channel 0, second becomes channel 1, etc). Instrument definitions
 are removed. Number of channels is highest number declared, or enough to
 contain as many channels as are used.

demuxpatel: reads in a single file defining more than one channel from
 standard input, writes out set of files, one for each output. Arguments
 must be filenames for each channel output (IE: first argument is filename
 for channel 0, etc). Instrument definitions are removed.

catpatel: reads in set of files, writes out all files concatenated into one
 to the standard output. Instrument definitions are removed. Number of
 channels is highest number declared.

repeatpatel: reads in single file from standard input, sends it repeated to
 standard output the number of times specified in the only argument.

(cut and shift utilities should be done when details for them figured out :) )

trackpatel: single-track, single pattern (of any length) tracker-style
 GUI editor for PPF files. Will reject files with more than one track.
 Might give it ability to modify instruments? Or should that be a
 separate editor? Needs to be able to use more than one instrument in the
 same channel though, I think. Can run Patel directly on the file being
 worked on in order to test how it sounds.

notestoppf.pl: takes set of files (or standard input) containing score for
 one track with one instrument, in another bespoke (but more human-friendly)
 format, and produces a PPF version on standard output, with channel number
 0 and instrument number 0. Header declares 4 channels and 1 instrument,
 single instrument definition is empty.

remappatel: reads in file from standard input, sends it to standard output
 with all occurrences of instrument specified in first argument changed to
 instrument specified in second argument. Useful for mixing channels made
 for different sets of instruments. Does no remapping of instrument
 definitions (which would be awkward/impossible).

extractpatel: reads in file from standard input, writes set of instrument
 definitions found there to standard output.

Stuff for processing instruments
