Simple java consumer

Creates a simple blocking java consumer.  It is expected that this code is executed inside of a thread (or something similar)


```ruby
# $bundle exec jruby hermann_test.rb


require 'hermann'
require 'hermann/provider/java_simple_consumer'
require 'hermann_jars'

zookeeper = "localhost:2181"
groupId   = "group1"
topic     = 'test'

example = Hermann::Provider::JavaSimpleConsumer.new(zookeeper, groupId, topic)

example.get_messages do |msg|
  puts "Recv: #{msg}"
end
```

In the context of the test, I'm not explicitly testing the ```#createMessageStreams``` so the keyword allow is used (even tho they do the same thing).  The main thing I want to test is the next line, so I don't want to focus the reader on the allow line.