Feat/depolar reset (#129)

* Add depolarizing model reset

Author: ciaranra

python/quantum-pecos/src/pecos/error_models/error_depolar.py

@@ -77,6 +77,9 @@ def start(self, circuit, error_params, reset_leakage=True):
 
         return self.error_circuits
 
+    def reset(self):
+        return DepolarizingErrorModel()
+
     def generate_tick_errors(
         self,
         tick_circuit,