* Updating thrift definitions to add autopause for batch based update strategies.
* Adding batch calculator utility and test cases for it.
* Adding PauseUpdateMonitor which allows users to poll Aurora for information on an active Update being carried out until it enters the ROLL_FORWARD_PAUSED state.
* Tests for PauseUpdateMonitor and VariableBatchStep added to the end to end tests.
* Adding TerminalUpdateStates function which returns a slice containing all terminal states for an update. Changed signature of JobUpdateStatus from using a map for desired states to a slice. A map is no longer necessary with the new version of thrift and only adds complexity.
* Adding Aurora URL validator in order to handle scenarios where incomplete information is passed to the client. The client will do its best to guess the missing information such as protocol and port.
* Upgraded to testify 1.3.0.
* Added configuration to fail on a non-temporary error. This is reverting to the original behavior of the retry mechanism. However, this allows the user to opt to fail in a non-temporary error.
