Fix Python 2 string handling in osc_types.get_string

pythonosc/parsing/osc_types.py

@@ -61,7 +61,7 @@ def get_string(dgram, start_index):
   """
   offset = 0
   try:
-    while dgram[start_index + offset] != 0:
+    while dgram[start_index + offset] != '\x00':
       offset += 1
     if offset == 0:
       raise ParseError(