Enhanced array appending

[Steven Schveighoffer]

bearophile Wrote:

> Steven Schveighoffer:
> 
> >The new code beats the old runtime in both tests<
> 
> Are you testing Phobos or Tango? Because I think Tango may have a performance bug there that's missing in Phobos (another even worse performance bug that I think is present in Tango is on the isIn_r of built in associative arrays).

D2, so phobos.

-Steve