Ease Installation

Completed work for #4 "Support arbitrary bin sizes in hot spot analysis".

BamLiquidator is now easier to install and upgrade, leveraging apt-get install and pip.  Installation instructions are at https://github.com/BradnerLab/pipeline/wiki/bamliquidator#Install .

`apt-get install bamliquidator` uses a debian package at the following ppa:

https://launchpad.net/~bradner-computation/+archive/pipeline

`pip install BamLiquidatorBatch` uses the python module here:

https://pypi.python.org/pypi/BamLiquidatorBatch/

Note that I re-organized a lot of the files for the creation of the debian package and the pip module.  Updates to the debian package and python modules can be uploaded with `make dput` and `make pip` respectively (under the bamliquidator_internal directory).

Test plan:
1. test the install instructions
2. regression test bamliquidator: try a uniform bin run, try a region run, try running flattener, try running bamliquidator (not bamliquidator_batch) and confirm everything is found properly on the default search path (without having to provide a full path)
3. test the upgrade and uninstall instructions

Note that ideally pip wouldn't be needed, but bamliquidator_batch.py uses bokeh and bokeh currently isn't able to be installed with apt-get.  I could probably get the install to work without pip by packaging up bokeh and all of bokeh's dependiences but this would probably take in excess of 16 hours of time.