dcollections version 0.02

[dsimcha]

Nice work.  This brings to the table a lot of stuff that I really felt was missing
in D2.  One quick question, though.  Given that associative arrays are built-in
and implemented as hash tables, are there any tradeoffs dcollections makes
differently than the builtins that would make me choose one over the other?  As a
hypothetical example, is the dcollections HashMap more tuned for space at the
expense of speed, or vice-versa than the builtin?