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
thanks Louis for spotting those mistakes : I forgot to rewrite the doc when I switched from a Map for successes , to a set of keys only (we don't need the values that were inserted successfully, since we can retrieve them)
It's fixed now