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
```

```
[4] pry(main)> properties = Hermann::JavaUtil::Properties.new
=> {}
[5] pry(main)> properties.put("a", "1")
=> nil
[6] pry(main)> properties
=> {"a"=>"1"}
[7] pry(main)> properties.class
=> Java::JavaUtil::Properties
[9] pry(main)> properties == {"a" => "1"}
=> true  
````
Since a Properties seems equivalent to a hash going to test it that way