ModelWidget: now 'model' is a protected field 'commitedModel', setter/getter were added
Model: copy constructor and operator were deleted, move is allowed
FigureVisitor: accept(BoundedFigure) was added, throws newly introduced visitor_implementation_not_found() exception
model: figure cloning function was added, model copy consturctor was added
figures::SegmentConnection: copy constructor and assignment operator were deleted
model.cpp: got rid of warning: int --> size_t
modelwidget: now recognize() is called and the result is displayed during mouse movements (#17)
recognition: now recognize() function returns pointer to the modified/added/deleted figure
modelwidget: now modified figure is highlighted (#17), color of current track was made more transparent