Big changes in how the automatic model-free protocol is executed.
The call to gui_bieri.execution.calc_modelfree.start_modelfree() has been eliminated. This has been
replaced by a call to self.execute(). This new method assembles the data required for the protocol
from the relax data store (by calling self.assemble_data() which doesn't exist yet), and then starts
and stores the thread which is executing dAuvergne_protocol.
