Tables.waitForTableToBecomeActive optional params

Tables.waitForTableToBecomeActive now includes optional timeout and
interval parameters so callers do not have to wait 10 minutes
Adapt DynamoDB sample to use util.Tables

Since doesTableExist and waitForTableToBecomeActive now exist in
util.Tables, adapt DynamoDB sample to use them.
Version 1.7.1 of the AWS Java SDK

This release updates the Amazon Route 53 client to support the latest service features and also includes a number of improvements and fixes.
Merge pull request #167 from kenklin/master

Tables.waitForTableToBecomeActive optional params