Updated string quoting

Converts passed integers and bool to string, used to prevent string.encode() from erroring.

asterisk/agi.py

@@ -113,6 +113,9 @@ class AGI:
         sys.stderr.write('\n')
 
     def _quote(self, string):
+     """ provides double quotes to string, converts int/bool to string """
+        if isinstance(string, int):
+          string = str(string)
         return ''.join(['"', string.encode('ascii', 'ignore'), '"'])
 
     def _handle_sighup(self, signum, frame):