Closes #237

As stupid as "//path" vs "/path".
Even though the 1st option is perfectly valid path on Linux.

Somehow the issue only manifests itself under bitwig.

Fixes #298

Closes #336

All u-he plugins throw/abort when loaded in carla.
I don't really know the reason, but loading them in bridges works.
So for all known u-he plugins simply force bridge mode.
Take the chance and add calf-analyzer and ir.lv2 in there.
Closes #333
Closes #302

Since JACK1 runs the rt and non-rt events on the same thread,
blocking in the non-rt events can still cause xruns.
So now on non-rt JACK events we simply save the event to handle
later on a separate thread.
This was never an issue with JACK2 and the original code could be
kept, but I don't want to have 2 different implementations for
each JACK version (possibly leaving one untested).

(needs a full rebuild of carla and bridges)

Does not yet fix the infamous bug #234,
but some audio passes through now.
Still don't really know what's going on...

Also some needed cleanup