Segment == Named tuple

(why reinvent the wheel ?)
Timeline == banyan.SortedSet
Bug fix: DataFrame.sort_index returns None when called with inplace=True
Use new Timeline.union() in place of Timeline.__add__
Use new Timeline.add() in place of Timeline.__iadd__()
Timeline.union() bug fix

Prevent empty segments from being added to timeline segmentation.
Bug fix in depth-first search iterator
Documentation update
Use .timeline property when possible
PEP8
Segment == Named tuple

(why reinvent the wheel ?)
Timeline == banyan.SortedSet
Bug fix: DataFrame.sort_index returns None when called with inplace=True
Use new Timeline.union() in place of Timeline.__add__
Use new Timeline.add() in place of Timeline.__iadd__()
Timeline.union() bug fix

Prevent empty segments from being added to timeline segmentation.
Bug fix in depth-first search iterator
Documentation update
Use .timeline property when possible
PEP8