Added support for the ccm updatelog4jconf, feature allows to update Cassandra log4j configuration file (log4j-server.properties). See, JIRA for details, https://issues.apache.org/jira/browse/CASSANDRA-5322
CASSANDRA-5322: Implemented ccm setlog with java class name and log level clister wide or per node, implemented (updated last implementation) ccm updatelog4j configuration file, cluster wide or per node
CR change: changed ''.join to os.path.join
CASSANDRA-5322: made changes to follow CR down by Sylvain Lebresne
Merge pull request #62 from azarutin/advances_logging

Advances logging