Better schedule, including plotting

• plot_schedule method that plots the schedule
• forward_slack and backward_slack
• Execution times supported
• Slightly different graph_id that more often do not change the previous
• scipy is now a dependency for drawing splines

Close #35 (closed)

b_asic/schema.py

@@ -165,7 +165,6 @@ class Schema:
 
                     self._start_times[op.graph_id] = op_start_time
         self._remove_delays()
-        print(self._laps)
 
     def plot_schedule(self) -> None:
         def _draw_arrow2(start, end):