pip install error - cython required to install from tarball?
0.16 install from pip on ubuntu 12.04 LTS 64 bit edition currently throws an error:

Exception: Cython-generated file 'pandas/msgpack.c' not found.
Cython is required to compile pandas from a development branch.
Please install Cython or download a release package of pandas.

I did not specify a dev branch install from pip, simply ran

`sudo pip install pandas` and it produced the above error, python-dev and build-essential are installed, available and the latest updates on ubuntu 12.04 64
