RF: remove python 2.6 mpkg build

Python 2.6 binary installer on OSX now appears to be too old to use up-to-date
pip for installing - it gives SSL certificate errors:

https://github.com/pypa/pip/issues/829

Remove Python 2.6 OSX binary builders.
RF: use setuptools bootstrap script to install setuptools

Running into version conflicts installing setuptools with pip.
RF: use git for nose dev install

Newest pip won't install external files for pip as in nose==dev; use git URL
install instead.
NF: add numpy git scheduler for regular builds