allow router to override selection based on config
adding missing header
default async timeout to server idle timeout
use async gzip filter for async servlet
default query timeout to server idle timeout
Merge branch 'master' into smarter-router

Conflicts:
	services/src/main/java/io/druid/cli/RouterJettyServerInitializer.java
Merge pull request #645 from metamx/smarter-router

Allow router to override selection based on config