Implement file format for text images

[pkulev]

Abstract

We need file format to keep 3 things together:

• text image of object (now hardcoded in class definitions in form of lists passed to Surface constructor)
• layer of same size with color codes instead of image characters (now this feature barely usable via style parameter of Surface)
• additional layer with attributes like bold, blink, reverse.

Application itself must register colors and attributes it uses or just use defaults.

Example

[meta]
name = "kekstrel"

[layers]
image = """
  O  
<=H=>
 * * 
"""

# w is white
# b is blue
color = """
  w  
wwwww
 b b 
"""

# n is normal
# B is bold
attr = """
  n  
nnnnn
 B B 
"""

Implementation

Add classmethod Surface.from_file(). Replace hardcoded images with files, set path to them in corresponding configs.