Cassandra appender for Log4j.

Motivation and usage.
----------------------
Log4j is widely used as logging tool. A Cassandra implementation
used in Asynchronous way as well as having a local FileAppender
would facilitate offline log exploration and analysis.

An Asynchronous appender wrapping CassandraAppender is encourage
to avoid slowing down the applicaction. 

Adding appender to log4j.properties
----------------------

Add this appender to log4j.properties. See log4j-example.properties.

    # Cassandra Appender
    log4j.appender.CASS=com.datastax.logging.appender.CassandraAppender
    
    # Optional settings. The current values are the default ones
    #log4j.appender.CASS.hosts = 127.0.0.1
    #log4j.appender.CASS.port = 9160
    #log4j.appender.CASS.keyspaceName = "Logging"
    #log4j.appender.CASS.columnFamily = "log_entries"
    #log4j.appender.CASS.replicationFactor = 1
    #log4j.appender.CASS.consistencyLevelWrite = "ONE"
    #log4j.appender.CASS.maxBufferedRows = 1


How to build:
----------------------

  mvn install

If you are a maven user, maven dependency plugin can resolve the dependencies.
The following is an output of mvn dependency:list
  
Dependencies: mvn dependency:list
----------------------

	commons-codec:commons-codec:jar:1.3:compile
	commons-lang:commons-lang:jar:2.4:compile
	commons-logging:commons-logging:jar:1.1.1:compile
	javax.servlet:servlet-api:jar:2.5:compile
	junit:junit:jar:4.8.1:test
	log4j:log4j:jar:1.2.16:compile
	org.apache.cassandra:cassandra-thrift:jar:1.0.7:compile
	org.apache.httpcomponents:httpclient:jar:4.0.1:compile
	org.apache.httpcomponents:httpcore:jar:4.0.1:compile
	org.apache.thrift:libthrift:jar:0.6.1:compile
	org.slf4j:slf4j-api:jar:1.6.1:compile
	org.slf4j:slf4j-log4j12:jar:1.6.1:compile

mvn dependency:tree:
---------------------

	+- org.apache.cassandra:cassandra-thrift:jar:1.0.7:compile
	|  +- commons-lang:commons-lang:jar:2.4:compile
	|  +- org.slf4j:slf4j-api:jar:1.6.1:compile
	|  \- org.apache.thrift:libthrift:jar:0.6.1:compile
	|     +- javax.servlet:servlet-api:jar:2.5:compile
	|     \- org.apache.httpcomponents:httpclient:jar:4.0.1:compile
	|        +- org.apache.httpcomponents:httpcore:jar:4.0.1:compile
	|        +- commons-logging:commons-logging:jar:1.1.1:compile
	|        \- commons-codec:commons-codec:jar:1.3:compile
	+- log4j:log4j:jar:1.2.16:compile
	+- org.slf4j:slf4j-log4j12:jar:1.6.1:compile