Deprecate np.testing.importall - it's pointless and partially broken.

Add `print_function` to all `from __future__ import ...` statements
and use the python3 print function syntax everywhere.

Closes #3078.

The new import `absolute_import` is added the `from __future__ import`
statement and The 2to3 `import` fixer is run to make the imports
compatible. There are several things that need to be dealt with to make
this work.

1) Files meant to be run as scripts run in a different environment than
files imported as part of a package, and so changes to those files need
to be skipped. The affected script files are:

    * all setup.py files
    * numpy/core/code_generators/generate_umath.py
    * numpy/core/code_generators/generate_numpy_api.py
    * numpy/core/code_generators/generate_ufunc_api.py

2) Some imported modules are not available as they are created during
the build process and consequently 2to3 is unable to handle them
correctly. Files that import those modules need a bit of extra work.
The affected files are:

    * core/__init__.py,
    * core/numeric.py,
    * core/_internal.py,
    * core/arrayprint.py,
    * core/fromnumeric.py,
    * numpy/__init__.py,
    * lib/npyio.py,
    * lib/function_base.py,
    * fft/fftpack.py,
    * random/__init__.py

Closes #3172

This should be harmless, as we already are division clean. However,
placement of this import takes some care. In the future a script
can be used to append new features without worry, at least until
such time as it exceeds a single line. Having that ability will
make it easier to deal with absolute imports and printing updates.

- ParametricTestCase 
- The following arguments from numpy.testing.Tester.test(): level, 
verbosity, 
  all, sys_argv, testcase_pattern
- Path manipulation functions: set_package_path, set_local_path, 
restore_path
- NumpyTestCase, NumpyTest

Also separated testing parameter setup from NoseTester.test into 
NoseTester.prepare_test_args for use in a utility script for valgrind 
testing (see NumPy ticket #784).

Added numpy.testing.run_module_suite to simplify "if __name__ == '__main__'" boilerplate code in test 
modules.
Removed numpy/testing/pkgtester.py since it just consisted of an import statement after porting SciPy r4424.
Allow numpy.*.test() to accept the old keyword arguments (but issue a deprecation warning when old arguments 
are seen).
numpy.*.test() returns a test result object as before.
Fixed typo in distutils doc.

(prevent import of nose until actual execution of tests).  Restored 
"raises" function to numpy/testing/utils.py until it can be replaced with the function of 
the same name from nose.tools after the lazy import.