* Description *should* be wrapped at 80 chars (see e.g. Dijkstra's description)
* First line *should* be *more* descriptive
* No need to define package :) (redundant with namespace)
* Extend description to describe some edge cases (related to what was done in #62)
   * Distance between isolated Vertices?
   * Are parallel (multiple) edges supported?
   * Expected results for negative edge weights?
   * Expected results for negative cycles?
   * Expected results for null Graph (no vertices), edgeless Graph?
   * Distance between Vertex A and Vertex A? What about Loops? What about negative Loops?