fix config defines (mainly OSX LTC|portmidi|jackmidi)
various [inter] related build-system fixes:

* xjadeo depends in generated paths.h
* allow to set custom qmake parameters
* fix jack-midi/session detection (use pkg-onfig cflags/libs)
* cleanup whitespace in configure.ac
* use CPPFLAGS with configure on OSX.
* clean static linux pbuilds
update windows build script. prepare for pbuilder
use jack_free() fixes small memory leak
allow to disable Sync-Source and File actions
amend XDG_CONFIG_HOME support for OSX
use DnD for GLX (and fixes X11/XV)
update ChangeLog