Implemented Rate Segment Feature

Initial commit of Rate Segment Feature.
Added drawing of rated segment in magenta color.

Added drawing of rated segment in magenta color.  Drawing happens
continually after the first point of the segment has been chosen.
Renaming of variables for clarity.

Renaming of variables for clarity, and line formatting.
Merge pull request #22 from mafiglio/Feature_RateTripSegments

Feature rate trip segments