2) Create SegmentLoader interface for the loading of segments!
3) Setup serialization of new format and conversion function inside IndexIO
4) Make some adjustments to the twitter demo to make it make a bit more sense based on some email feedback from someone kicking the tires.
2) Add some docs to InputRow/Row to indicate that column names passed into the methods are *always* lowercase and that the rows need to act accordingly. (fixes#29, or at least clarifies the behavior...)