removed limit from single_stream as it is in info_stream
finished debugging info_stream and token stream
finished TextStreamer.to_vw and cleaned up docs
naming adjustments in TextStreamer
added info_stream caching for TextIterStreamer.to_vw
Merge pull request #12 from columbia-applied-data-science/streamers

Streamers - Added new TextIterStreamer and updated functionality in TextFileStreamer