added missing license header
added an IdService to create all IDs
SWF tasks have IDs now
Changes based on code review.
UUID assertion added
let's not wait too long for a task
test workflow execution info caching
allow MockCachedMapBuilder to have a factory for CachedMap creation
Merge pull request #407 from claymccoy/betterWorkflowIds

SWF Workflow Executions have Task IDs now