Allow to stop Handler when processing a request

[paneq]

Force stop

[paneq]

I am not sure this is safely possible with current state of ruby. Definitely not trivial:

http://blog.headius.com/2008/02/ruby-threadraise-threadkill-timeoutrb.html
http://docs.oracle.com/javase/1.5.0/docs/guide/misc/threadPrimitiveDeprecation.html