To provide a base class for all rendering nodes.
This is the class that handles colors. Colors in PDF::FromHTML::Template are specified in RGB format, comma-separated. Each number is from 0 to 255, with 0 being none and 255 being most. If a color is not specified, 0 is assumed. Thus, "255,0,0", "255,0", and "255" will all result in a red color.
Colors should be used for all attributes that have the word "COLOR" in the name. This includes (but may not be limited to):