Add Abort functionality

Adding async.Abort, which is an exception that when thrown within a job
causes the job to immediately execute with only a logging message and no
callbacks executed.
Add configuration module
Add clarifying statement to Abort docstr.

Add a statement to the Abort docstr indicating that only an info level
log message will be output upon Abortion.
In test_Abort, add checks on logging and start

In the test_Abort test, I added a check to ensure that Async.start() is
not called. Also, I added checks on logging.info() and logging.error()
to ensure that info is called and error is not.
Add logging intercept to test_Abort

Add a logging handler to the root logger that will throw an Exception
upon receiving a log message with an Error level or greater level.
Merge branch 'master' into add_abort
Merge branch 'master' of git://github.com/WebFilings/furious into config
Refactor and document based on code review
Correct bug with instantiating _local_context as a thread.local.

_local_context is initialized within the init context method.  This is
causing the thread local to be incorrectly initialized and
consequently get corrupted.
Merge pull request #57 from WebFilings/context_init_error

Correct bug with instantiating _local_context as a thread.local.
Change tests to use absolute imports

Clean config comments
Merge pull request #51 from johnlockwood-wf/config

Add configuration module
Split _parse_yaml_config into loading and parsing parts

In order to be more flexible and easily unit testable, split the loading
of the furious.yaml and the parsing of the yaml into two separate
functions.  This will reduce the required patching of file loading stuff
required, and make it possible to support other config loading
mechanisms.
Clean up config tests
Retrieve and run app engine tasks from testbed queues

The purpose is to run full local integration tests with the appengine
testbed.
Add check for InvalidYamlFile
Move to test-stubs/appengine/queues.py
Add test furious yaml file
Rename test file
Use underscore in dir name instead of dash