Fix decode test to actually decode message from stdin

scripts/capnp_test_pycapnp.py

@@ -1,4 +1,5 @@
 #!/usr/bin/env python
+from __future__ import print_function
 import capnp
 import os
 capnp.add_import_hook([os.getcwd(), "/usr/local/include/"]) # change this to be auto-detected?
@@ -8,13 +9,14 @@ import test_capnp
 import sys
 
 def decode(name):
-    print getattr(test_capnp, name)._short_str()
+    class_name = name[0].upper() + name[1:]
+    print(getattr(test_capnp, class_name).from_bytes(sys.stdin.read())._short_str())
 
 def encode(name):
     val = getattr(test_capnp, name)
     class_name = name[0].upper() + name[1:]
     message = getattr(test_capnp, class_name).from_dict(val.to_dict())
-    print message.to_bytes()
+    print(message.to_bytes())
 
 if sys.argv[1] == 'decode':
     decode(sys.argv[2])