adding a new command "fancysection", that uses a gradient color bar for each section, instead of a uniformly coloured bar
added variables and commands for setting the style and color(s) of the fancy shaded section bar
added more logic to the new fancysection command, to differ between shaded/plain section, plus if a middle color was set or not. the user can now set height, length, style (plain/shaded) and iff shaded its colors (left/right/middle)