Fix phased restart with worker shutdown timeout

[ebeigarts]

This pull request fixes phased restart with worker shutdown timeout.

This is from our production stderr log:

.../bundle/ruby/2.1.0/gems/puma-2.10.2/lib/puma/cluster.rb:76:in `term': undefined method `[]' for nil:NilClass (NoMethodError)
from .../bundle/ruby/2.1.0/gems/puma-2.10.2/lib/puma/cluster.rb:169:in `check_workers'
from .../bundle/ruby/2.1.0/gems/puma-2.10.2/lib/puma/cluster.rb:408:in `run'
from .../bundle/ruby/2.1.0/gems/puma-2.10.2/lib/puma/cli.rb:507:in `run'
from .../bundle/ruby/2.1.0/gems/puma-2.10.2/bin/puma-wild:31:in `<main>'

This bug was introduced in 2.10 with #566

lib/puma/cluster.rb:76:

if @first_term_sent && (Time.new - @first_term_sent) > @options[:worker_shutdown_timeout]

The problem is that @options are not passed down to cluster workers.

I also changed Events class a bit, so that it doesn't throw everything
to STDOUT/STDERR when in cluster mode.

[tmikoss]

+1