Issue 110 : bulkOperations integration tests

Several things to review here :
* the integration tests of course
* some rewrites of the putAll and removeAll methods (with some refactorings too)
Thanks for your input in advance
Let's discuss the implementation of this method when you're around Anthony.
I'm pulling your changes in for merging this in this morning, but I think this is still a bogus implementation... Now I could well be missing something here!