Prepare for PyPI, add console script, updates to CLI date parsing

Includes a number of changes for packaging and release on PyPI:

* create congressionalrecord module and move existing content inside
* update setup.py to remove unnecessary requirements
* add console_scripts so parsecr can be run from anywhere
* add @LindsayYoung to setup.py author info

Extracted some date util methods from the CLI. They'll need to be moved out to somewhere reusable later, but this is a start. Also updated the parsing of the command line date arguments so more complex date ranges can be passed:

    parsecr 2014-01-28:2014-01-30 2014-02-05 2014-02-12:2014-02-14 

Fixed a bug (that I may have introduced) in default output directory that caused dates to be nested inside each other on the filesystem.