Fix most trivially-findable print statements.

There's one major and one minor category still unfixed:
doctests are the major category (and I hope to be able to augment the
refactoring tool to refactor bona fide doctests soon);
other code generating print statements in strings is the minor category.

(Oh, and I don't know if the compiler package works.)

Lib/Bastion.py

@@ -165,7 +165,7 @@ def _test():
         print "accessible"
     \n"""
     exec(testcode)
-    print '='*20, "Using rexec:", '='*20
+    print('='*20, "Using rexec:", '='*20)
     import rexec
     r = rexec.RExec()
     m = r.add_module('__main__')