Initial switch to setup.py driven building

A work-in-progress, do not merge

Needed to enable sane builds that are uploadable to PyPI and to enable accurate c++ code coverage measurement. Will fix Jenkins build issue as well and do your dishes.

to test:
# make a clean virtualenv and activate it
virtualenv env
. env/bin/activate
# ensure that there is no other copy of khmer installed
echo import khmer | python # should produce an error
# use pip uninstall khmer or other method to remove khmer from the virtual env
pip uninstall setuptools # to test autoinstall of setuptools thanks to ez_setup.py
pip install screed
python python/setup.py install

#scripts are now in env/bin/*.py
load-into-counting.py # and so forth

#to run built in tests
python python/setup.py develop
nosetests -v -x -a \!known_failing

This needs testing on Mac OS X

TODO: port all the options from the Makefiles and remove the Makefiles
TODO: more sugar for the PyPI distribution (trove_classifiers, long_description)
TODO: support the test and nosetests commands
TODO: test making RPMs, DEBs via setuptools; support linking against system zlib and bzip2 for these cases
TODO: test support for --user installs
TODO: only build zlib and bzip2 when needed
TODO: ensure that the sdist command produces a tarball that includes all files needed to build from source