More text-based render styles

[AnonymouX47]

I plan to add the following styles:

• ascii: Using ASCII characters with varying density to represent the greyscale form of an image.
• braille: Using braille patterns (the full +U2800 to +U28FF range) to represent the greyscale form of an image.
• blank: Using blanks (spaces) with background colors.

I'll appreciate suggestions about more styles. 😃

I'll update the list as more ideas or suggestions come.