Created a HeatmapImagegenerator class for generating images from heatmaps.
Implemented a Generate method in HeatmapImagegenerator that handles the generation of images.
Fixed a few Heatmap documentation typos.
The Generate method handles invalid arguments by throwing exceptions.
Added documentation for the HeatmapImagegenerator class.
The Generate method allows null as width/height argument.
Created a method in HeatmapImagegenerator that calculates the color at a given point between two colors.
Implemented two methods for generating Heatmaps using two or three colors.
Merge remote-tracking branch 'origin/master'