Initial switch to setup.py driven building

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
python -c "import khmer" # should produce an error
#if no error then 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
python setup.py install
python setup.py sdist
python setup.py bdist

#scripts are now in env/bin/*.py
load-into-counting.py # and so forth

#to run built in tests
python setup.py nosetests