More logging in Wallace and --max-tasks per process option for wallaced
Summary: Given that part of https://git.kolab.org/D761 changes are obsolete after commit baeee0049f06430801a2d9940f875747e51be7f5 I still want to have some changes find their way in master.
Test Plan: None
Reviewers: vanmeeuwen
Subscribers: petersen, machniak, vanmeeuwen
Differential Revision: https://git.kolab.org/D791