added draw method to circuit (#266)

* added draw method to circuit (warning about font comes up in linux env)

tangelo/linq/circuit.py

@@ -22,6 +22,7 @@
 from typing import List
 
 import numpy as np
+from cirq.contrib.svg import SVGCircuit
 
 from tangelo.linq import Gate
 
@@ -144,6 +145,15 @@ def is_mixed_state(self):
         """
         return "MEASURE" in self.counts
 
+    def draw(self):
+        """Method to output a prettier version of the circuit for use in jupyter notebooks that uses cirq SVGCircuit"""
+        # circular import
+        from tangelo.linq.translator.translate_cirq import translate_c_to_cirq
+        cirq_circ = translate_c_to_cirq(self)
+        # Remove identity gates that are added in translate_c_to_cirq (to ensure all qubits are initialized) before drawing.
+        cirq_circ.__delitem__(0)
+        return SVGCircuit(cirq_circ)
+
     def copy(self):
         """Return a deepcopy of circuit"""
         return Circuit(copy.deepcopy(self._gates), n_qubits=self._qubits_simulated, name=self.name)