patch by rvieira reviewed by dbrosius for cassandra-5647
Patch by marcuse, reviewed by jbellis and carlyeks for CASSANDRA-5535
patch by dbrosius reviewed by slebresne for CASSANDRA-5533
patch by jbellis; reviewed by jasobrown for CASSANDRA-5497
patch by jasobrown; reviewed by jbellis for CASSANDRA-5393
patch by dbrosius reviewed by jbellis for CASSANDRA-5464
…cluster. This version slightly refactors Gossiper by pulling th seeds list building code out of start() and into a shared method that removeEndpoint() will call. Also, reload the seeds list, then remove the dead node.
patch by jbellis; reviewed by dbrosius for CASSANDRA-4463