dcollections version 0.02

[maelp]

> You can find a very efficient stack in the new Tango containers.

This raises the questions:
a. How does the structures from dcollection and Tango compare, in terms of integration to tango, speed, memory efficiency, richness of API?
b. Why aren't the efforts of both libraries combined ? Dcollection is maybe not mature enough ? Are there plans to merge them if dcollections happen to be more efficient ?