Update Python build scripts to use the print function

In Python 3, 'print' was changed from a statement to a function.  Using
the __future__ module allows scripts to use print function whether
running with Python 2.6+ or Python 3.x.  This commit changes as many
instances of print as I could find to use the print function and the
__future__ module.

utils/swift-bench.py

@@ -34,6 +34,8 @@
 # Ideas for the harness improvement and development are welcomed here:
 # rdar://problem/18072938
 
+from __future__ import print_function
+
 import subprocess
 import numpy
 import time