[Configobj-develop] Example in documentation

[<m.g...@gm...>]

Hello, 

first: great software, regrettably one funktion is complex; i try to change 
the sectionname. I read the documentation and a hint to read the code, 
because i dont`t understand it. 

can you add a small example in the documentation with "call_on_sections =  
True". 

Marc