Added "None" keyword to create files without extension after exraction

I am not sure where to add "None" extension handler. 

I faced a problem when I am extracting custom firmware with {file-name} already having an extension(ex: index.html, ring.wav, binary.elf and etc).
 
Before the patch with the following extractor.conf:
"file in firmware:None"

I extracted the following files:
index.html.None
ring.wav.None
binary.elf.None

after the binwalk patching i have the following files:
index.html
ring.wav
binary.elf