v0.8.1

Some new functionality:

• --http_errrors and --connection_errors to control how many times to keep trying after low level connection errors. Thanks @justinlittman!
• --geocode to limit search results to a particular location & radius. Thanks @chosak!
• utils/geofilter.py for filtering in/out tweets with any geo information or geo information within a particular fence. Thanks @chosak again!