ENH: Bump FFTW to 3.3.3.

Also use midas3.kitware.com to host the tarball and improve download
reliability.

Change-Id: Icae54c78687319f55d9a3dd41bc28eeff53f16dd
ENH: Use python warnings module for template warnings

I changed the output of the warnings to go through the warnings module.
See : http://docs.python.org/library/warnings.html

The warnings are still sent to stderr by the warnings module.
The warnings are also formatted to not display the filename and the linenumbers, as this will always
display the same lines in itkTemplate.py

Users can now disable warnings with the following lines before importing ITK :
import warnings
warnings.filterwarnings("ignore")

or by running python with : python -W ignore foo.py
Merge topic 'Python-warnings'

16e346b7 ENH: Use python warnings module for template warnings
STYLE: Coverity 1103107-1103116: Logically dead code

Change-Id: I3bfe33d0d563a09c0cfc5c3f019b6c18b25d56dd
Merge topic 'cov_1103107'

3e4187fa STYLE: Coverity 1103107-1103116: Logically dead code
Merge topic 'fftw-midas2'

7a4fb5b4 ENH: Bump FFTW to 3.3.3.