Bug 553577 - Async completion can cause StackOverflowError

+ Reduce amount of calls to filterProposals() from AsyncCompletionProposalsPopup
+ Refactorings to ease readability and reduce "state" variables
+ Revise which futures we're waiting for before triggering filter

Change-Id: Ie52b626531d044e76ddab3516c336d43490e43b1
Signed-off-by: Mickael Istria <mistria@redhat.com>
1 file changed