Ascension

In this cycle we did a lot of finetuning on the gtk+3 port. More deprecated APIs
are replaced with the new API. We did a lot of work on theming; e.g. all colors
are now defined in the css files and settings let you select theme variants such
as a dark theme.
The interaction controller library now supports alsa-sequencer. The UI for
training the controls of a new midi device is streamlined and much easier. Also
the controls from the interaction controller can be used fro playback controls
(play/pause/seeking).
Finally things got easier for developers too. We merged bml, gst-buzztrax into
buzztrax to simplify the build.