simple parallel sim (async node)

verse/analysis/analysis_tree.py

@@ -110,8 +110,6 @@ class AnalysisTree:
         node_id = 0
         while queue:
             node = queue.pop(0)
-            print("NODE: ", node)
-            node.id = node_id 
             res.append(node)
             node_id += 1
             queue += node.child

verse/scenario/scenario.py

@@ -155,6 +155,7 @@ class ScenarioConfig:
     unsafe_continue: bool = False
     init_seg_length: int = 1000
     reachability_method: str = 'DRYVR'
+    parallel_sim_ahead: int = 8
 
 class Scenario:
     def __init__(self, config=ScenarioConfig()):