[Samba] Implementation suggestion

[Pablo Lopes Mesquita]

I would suggest to programmers that implanting a variant of the "veto
files" example: "Allow Files". Where I can tell you what file extensions
allowed in the share.
Another suggestion, would be to impose the option "!" For exceptions.
For there are cases where a share is only allowed x file types and it
becomes expensive to list all files not allowed.

Thank you