added check_datastax_opscenter_cluster_backups.pl
renamed check_datastax_opscenter_alerts.pl -> check_datastax_opscenter_cluster_alerts.pl
added keyspace opts
added note to desc that these require DataStax Enterprise Server
merged master
finished check_datastax_opscenter_cluster_backups.pl
finished initial basic version of check_datastax_opscenter_cluster_alerts.pl
added keyspace env var support
updated lib
Merge branch 'dev'