Kill lazy workers with TERM before KILL

We want to know what was going on with a lazy worker, KILL is un-trappable so we
are sending TERM instead, then to make sure the process really dies we are
KILLing a second later.
Kill lazy workers in two iterations TERM then KILL
Merge pull request #1 from camilo/give_rails_a_chance

Kill lazy workers with TERM before KILL