Assemble curves in c.

Requires a new version of qt-graph-helpers.
Moved gmm implementation from archive/gmm.
Display groups on widget.
Code style.
Set number of optimization steps as a parameter.
Fix crash when one cluster lost all members.
Fix scaling problem.
Seed clusters with kmeans.
Variable window size.
Remove debugging output.
Updated algorithm description
Default window size is 1.
Caching of computed groups.
Update algorithm description.
Define variables.