[PD] jack_transport improvements

[Jacob Lee]

I've added some code to the jack_transport external
(tb/jack_transport/ in pd-extended) to show the current bar/beat (and
also bpm and tempo) in real time. Messages are only sent out when pd
is computing audio, and also no more than once per beat (to avoid
floods of messages).

I'm not outputting all the available information from the jack
transport -- e.g. the current tick within the beat -- either because
it updates too quickly or because it's just not useful to me, but it
would be trivial to add those.

The motivation here is that I'm using klick --
http://das.nasophon.de/klick/ -- as the jack transport master (mainly
to control sooperlooper), and now it is possible to trigger events
within pd at particular beats or bar numbers.

The code is available at
http://artdent.homelinux.net/svn/jack_transport~/ . The makefile
should be suitable for building jack_transport~ from inside a
directory that is sibling to the existing jack_transport. I've only
tested it on Linux, but it should work anywhere jack_transport does.

I hope this external is useful to others. Suggestions for improvements
are of course welcome.

-- 
Jacob Lee
artdent at gmail.com