scaled_to_colors: Convert image output from scale_image() to bricks
In brickr: Emulate LEGO Bricks in 2D and 3D

Match raw color channel values to a smaller subset of colors.

`image_list`	List output from scale_image(). Contains an element `Img_scaled`.
`method`	Default 'cie94'. The method to use for comparison. Either 'brickr_classic', 'euclidean', 'cie1976', 'cie94', 'cie2000', or 'cmc'. 'brickr_classic' is an explicit euclidean distance formula, but yield different results than 'euclidean' in farver. See `farver::compare_colour`.
`color_table`	Defaults to `lego_colors`. Data frame of brick colors to map onto image. Must contain Name and R, G, B channels. See attached data `lego_colors` as examples.
`color_palette`	Brick color rarity to use. Defaults to all colors: 'universal' (most common), 'generic', and 'special' (least common). This is useful when trying to build the mosaic out of real bricks. Use "bw" for only grayscale bricks. Ignored if a `color_table` is supplied.
`trans_bg`	If `img` is a png has a transparent background, name of color to replace the background.
`dithering`	Improves color of large, photo-realistic mosaics.
`contrast`	For `color_palette = "bw"`. A value >1 will increase the contrast of the image while a positive value <1 will decrease the contrast.
`default_piece_type`	Piece type to use in absence of piece_type column.