Hi!

I uploaded my latest modifications to collections to the inbox. The 
suggested load/merge order is:

Collections-ul.144
Kernel-ul.251
Collections-ul.145

To load/merge these packages, you should have both Collections-ul.140 and 
Collections-ul.143 loaded/merged.

Since the trunk doesn't have enough tests for the Collections package I 
decided to load these changes into the latest pharo image and run the 
tests. All of them pass, except for the tests for 
WeakKeyToCollectionDictionary, but that's because of a bug in the tests 
(The tests add SmallIntegers as values instead of Collections to the 
dictionary. Unfortunately they all pass with the original implementation, 
because #rehash is never sent to the dictionary).

To see if it's worth (or not) to use these changes I wrote a small 
benchmark for Dictionary which can be found here: 
http://leves.web.elte.hu/collections/ .

Cheers,
Levente