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.
This allows Python or .gyb files to do "import gyb" and use the basic
components of the system. For example, we could create a Python
function to generate the boilerplate for a Mirror. That function could
use gyb.parseTemplate() to load an inline template and
gyb.executeTemplate() to generate the code. Then calls to that function
can be embedded in ${...} in a .gyb file.
Swift SVN r19490
