[Tagging] RFC - A broad look at fountains

[Davidoskky]

> In Australia it would be unusual to find a drinking fountain without a 
> tap to stop the flow when a person is not drinking. I think it could 
> be illegal such is the scarcity of water. 
Thus, I believe that a world wide default should be avoided in favour of 
local ones or enforcing explicit tagging.

tap=yes as default would not work in Italy and tap=no as default would 
not work in Australia.