Move from/to logic to Line#initialize
Use methods instead of instance variables in Rectangle
Modify Rectangle#initialize
Use #min and #max instead of Rectangle#width and Rectangle#height
Remove unnecessary logic from Rectangle#rasterize and unnecessary method Rectangle#border
Refractor Rectangle#rasterize
Refractor Line#rasterize
Hide class Bresenham in class Line
Use methods instead of instance variables in Point
Use HEADER and FOOTER instead of BEGINNING and ENDING
Make Ascii#render and Html#render normal methods
Use Renderers#Ascii logic in Renderers#Html
Use Canvas#each_pixel instead of Canvas#full_pixels
Initialize Bresenham with from and to points instead of line