Remove heartbeat doc (merged in pooling section).
Remove heartbeat doc (merged in pooling section).

kjniemi/java-driver,irudyak/java-driver,codefollower/Cassandra-Java-Driver-Research,DICL/cassandra-driver,tommystendahl/java-driver,tommystendahl/java-driver,cesarmarinhorj/java-driver,cesarmarinhorj/java-driver,pingtimeout/java-driver,joeljacobson/java-driver,mcanini/java-driver,joeljacobson/java-driver,fromanator/java-driver,tolbertam/java-driver,techkrish/java-driver,ptnapoleon/java-driver,amasta/java-driver,adejanovski/java-driver,a-burylov/java-driver,csm/java-driver,DICL/cassandra-driver,codefollower/Cassandra-Java-Driver-Research,csm/java-driver,kjniemi/java-driver,mcanini/java-driver,csm/java-driver,codefollower/Cassandra-Java-Driver-Research,irudyak/java-driver,pingtimeout/java-driver,ptnapoleon/java-driver,fromanator/java-driver,bsideup/java-driver,irudyak/java-driver,mcanini/java-driver,mike-tr-adamson/java-driver,adejanovski/java-driver,mebigfatguy/java-driver,amasta/java-driver,DICL/cassandra-driver,mebigfatguy/java-driver,a-burylov/java-driver,cesarmarinhorj/java-driver,techkrish/java-driver,mike-tr-adamson/java-driver,tommystendahl/java-driver,tolbertam/java-driver,bsideup/java-driver,mike-tr-adamson/java-driver,ptnapoleon/java-driver,fromanator/java-driver,pkdevbox/java-driver,techkrish/java-driver,kjniemi/java-driver,bsideup/java-driver,a-burylov/java-driver,adejanovski/java-driver,pkdevbox/java-driver,mebigfatguy/java-driver,amasta/java-driver,pkdevbox/java-driver,tolbertam/java-driver,pingtimeout/java-driver,joeljacobson/java-driver