Add ThreeColorLineSeries (#378)

CHANGELOG.md

@@ -16,6 +16,7 @@ All notable changes to this project will be documented in this file.
 - Added LinearBarSeries for WPF (#506)
 - Added TitleToolTip to PlotModel (#508)
 - Expose PlotElement's TextColor property on WPF.Axes.Axis (#452)
+- ThreeColorLineSeries (#378)
 
 ### Changed
 - Renamed OxyPlot.WindowsUniversal to OxyPlot.Windows (#242)

CONTRIBUTORS

@@ -49,6 +49,7 @@ Kevin Crowell <crowell@proteinmetrics.com>
 LECO® Corporation
 Levi Botelho <levi_botelho@hotmail.com>
 lsowen
+Luka B
 Matthew Leibowitz <mattleibow@live.com>
 Memphisch <memphis@machzwo.de>
 Mendel Monteiro-Beckerman