Version bump to v0.5.0

Quite a “large” release with a ton of changes, ranging from a rewrite of
how “configuration attributes” are managed to minor fixups:

* Removal of `zookeeper` recipe. Use a dedicated cookbook for that.
* Host all “configuration attributes” under a `broker` namespace.
* Configurable and sane log4j properties (see `attributes/default.rb`
  for examples).
* Configurable KAFKA_GC_LOG_OPTS environment variable through the
  `gc_log_opts` attribute.
* Bugfix for using this cookbook with AWS OpsWorks (thanks to @pfleidi).

metadata.rb

@@ -6,7 +6,7 @@
 license          'Apache 2.0'
 description      'Installs and configures a Kafka broker'
 long_description IO.read(File.join(File.dirname(__FILE__), 'README.md'))
-version          '0.4.1'
+version          '0.5.0'
 
 recipe 'kafka::source', 'Downloads, compiles and installs Kafka from source releases'
 recipe 'kafka::binary', 'Downloads, extracts and installs Kafka from binary releases'