use log messages instead of print
fetch_libzmq always downloads fresh libzmq

Forces a fresh download, which allows `./configure` to run.

Useful on platforms where the shipped platform.hpp does not work, but bundled libzmq is still necessary.

To use it:

pip install pyzmq --global-option="fetch_libzmq"
tweak sys.argv manipulation to ensure implied configure doesn't get inserted before fetch_libzmq
Merge pull request #354 from minrk/refreshzmq

fetch_libzmq always downloads fresh libzmq

Forces a fresh dowload of libzmq, which allows `./configure` to run.

Should be useful on platforms where the shipped platform.hpp does not work, but bundled libzmq is still necessary.

To use it:

    pip install pyzmq --global-option="fetch_libzmq"

Of course, this won't be available until the next release.

closes #333

I also changed all of the print() methods to info(), to avoid weird out-of-order issues due to writing to both stdout and stderr.