Python-airtable

* Merge Fix

* Moved version to sep file to fix setup.py error
* Removed urlencode import
* Added Explicit Raise for 422 errors with Decoded Urls

* Feature: Added airtable.get() method to retrieve record
* Fix: sort/field string input to allow sting or list
* Fix: AirtableAuth Docs
* Fix: Keyargs Docs

* Bugfix: Fix Setup to install six.py
* Bugfix: Fix AitableAuth Docs

* Implemented Sort Filter
* Implemented FilterByFormula
* Implemented all param filters as classes
* Added Aliases for Parameters
* Renamed get() to get_iter()