do some housekeeping in common.rb
do some housekeeping in common.rb

Move the dispatcher thread body into its own method.
Most things should be private in here.

rickypai/zookeeper,rickypai/zookeeper,songling88/zookeeper,songling88/zookeeper,rickypai/zookeeper,zk-ruby/zookeeper,songling88/zookeeper,rickypai/zookeeper,zk-ruby/zookeeper,zk-ruby/zookeeper,songling88/zookeeper