Added int to bigint migration, and the reverse.  Added BigIntEntity base class and inherit from that in the LoadBalancerHostUsage class.

Added lb_merged_host_usage table to also use bigint instead of int.
Added previousSslTermination instance variable and getters and setters into the MessageDataContainer.  Changed the usage code to make a smart decision abotu what counters to put into the lb_host_usage table based on the previous ssl term and the new one in the SslTerminationListener.