Rule idea: pinpoint functions with too many indentation levels

[erszcz]

Too deep indentation might signal that a function's logic is too complex. Even if it's not the case, too deeply indented code is hard to read and makes the programmer cramp the code on the far right side of the screen, especially when also using the max-80-chars-per-line rule. This is a real-world example of code cramped on the far right with a really exaggerated case here.

[elbrujohalcon]

Duplicate from #14