Remove array element within function

[Rekel]

I'm not sure if this is the place to talk about it, but on the 
same topic it's a little strange to me neither the Dlang Tour nor 
the arrays spec page mention removing elements. Even though 
basically everyone is going to use it sooner or later (most 
likely sooner).

Is that because it's part of the library? That's the only reason 
I could think of, while in a way I could make that argument for 
appending in the case it hadn't been given the `~` and `~=` 
operators.