Allow ActivityWorker to shutdown cleanly

ActivityWorker doesn't shutdown cleanly.

It registers a @shutdown_first_time_function in initialize that does a Kernel.exit on sigint/term.  But the exit exception is caught by the poller (task_poller.rb line 182), so the ActivityWorker continues the task polling loop.

This change just ends the loop if the worker is shutting down.
adding support for multiple exceptions in single async BRE ensure block and fixing a bug in jitter/retry
Latest doc updates
ActivityTaskPoller quits polling early

The ActivityTaskPoller fails to check for poll timeouts before logging information about the task.  As a result, it throws an exception, which is caught by the ActivityWorker, which just retries.  There's no real harm done, since the ActivityWorker retries the failed poll, but this cleans up the invalid log messages and lets the code behave as intended.
ForkingExecutor doesn't use provided logger config

Simple cleanup..
upgrading rspec to 2.14
fixing the rakefile and refactoring FakeServiceClient
removing debugger from Gemfile
Merge pull request #36 from pmohan6/master

Multiple bug fixes and rspec upgrade
Make ActivityWorker shutdown consistent with WorkflowWorker shutdown
Merge branch 'docs' of https://github.com/EronHennessey/aws-flow-ruby into master
Merge branch 'master' of https://github.com/YesVideo/aws-flow-ruby into master
Fix to the forking timeout issue. Now using a new connection pool for forked
processe. Also fixed some logging messages.
Bumping version to 1.0.9
Merge pull request #42 from pmohan6/master

Fixed forking timeout issue and log levels in task poller
updating version of aws-sdk dependency to 1.36.2
Merge pull request #43 from pmohan6/master

Updating version of aws-sdk dependency to 1.36.2
fixing the aws-sdk gem dependency
Merge pull request #44 from pmohan6/master

fixing the aws-sdk gem dependency
fixing uuidtools dependency and remove options ivar from Workflows module