Tags give the ability to mark specific points in history as being important
Fixed draw to work with varargs[Plot] for plot2D (contour plots)
Changed to symmetric 0 == black colorscheme for plot2D
Made plot2D (contour plots) consistent with other types of plots
Added basic keyboard input into the render proc
Made indexing and BackwardIndexing consistent
Added background colors for 1/2 char resolution, added png display
added toColor for changing plot cols after generating the Plot object