Added a json format option

This addition allows the user to get the raw json tweet information from each row. This is helpful when the twitter json format is needed by another process.

Example usage: `twitter --format=json -r friends`
Merge pull request #185 from cegme/json_status_dump

Added a json format option
This addition allows the user to get the raw json tweet information from each row. This is helpful when the twitter json format is needed by another process.

Example usage: `twitter --format=json  friends`

This would get the latest tweets from friends in the raw json format. That json can be ported into another process or another database for processing.