Update __init__.py
Update __init__.py

Add min_length and max_length parameters for class String to allow string length validation like in trafaret.List class. Sometimes it is useful, example: check password length.
Deepwalker/trafaret,rrader/trafaret,Deepwalker/trafaret,Deepwalker/trafaret,Axik/trafaret,Axik/trafaret,rrader/trafaret,Axik/trafaret,rrader/trafaret