[Http] Making it so that if a custom callback function used to determine if a request should be retried using exponential backoff returns null that the exponential backoff plugin will do the default checks to see if a request should be retried.
[Service] Moving magic method call behavior constants to Guzzle\Service\ClientInterface.  Adding magic method call behvaior to Guzzle\Service\Command\AbstractCommand similar to the magic method call behavior of Client objects.  When magic method calls are enabled on a client object, they become enabled on commands created by the client.  $command->setFoo("x") is the same as $command->set("foo", "x") when magic method calls are enabled.
[Service] Emitting an event each time a client is created through a ServiceBuilder.  Closes #44
Fixes a defect that always adds a hashtag (#) to every url.
Fixes Nonce Generation issue.  Multiple Requests with the exact same timestamp were using the same nonce.
Fixing OauthPlugin tests.  Adding test to cover the new fragment conditional used when building urls.
[Http] Fixing a bug in the CurlMulti object that changed the state of the object to idle when a higher scope completed, rather than wait for lower scopes to complete.  Moving the retry count of a request in the exponential backoff plugin to the request params object.  Rewinding request streams when retrying requests.  Using microtime when dealing with exponential backoff checks so that more granular backoff strategies can be utilized.
Fixing instances of HttpException since it was changed from a class to an interface
Renamed generic runtime exceptions to guzzle exceptions
Reverted test to type hint interfaces
Merge pull request #46 from missinglink/master

Fixing instances of HttpException since it was changed from a class to an interface
Lots of refactoring for *greatly* improved performance (4-5x faster)

[Http] cache.* parameters should be prefixed with 'params.' now.

Adding the ability to set arbitrary curl options that don't map to constants (disable_wire, progress, etc)

Added a check to the CurlMulti object that prevents sending a request when the curl multi resource has been destroyed.  This could possibly happen when issuing requests from a destructor.

Adding the ability to disable type validation of configuration options

Adding a cache for all requests owned by a curl multi object

Creating the polling event external to the main CurlMulti loop

Hardening the CurlMulti class so that curl handles that are finished sending are removed from the multi handle.  Adding validation test

[Common] BC: Simplifying Guzzle\Common\Collection so that it is more performant.

[Service] Adding the ability to disable validation on the Inpector class.  Disabling validation on first instantiating commands so that defaults are added but nothing is check until attempting to execute a command.

Using class properties instead of a Collection for ApiCommand

BC: Using a custom validation system that allows a flyweight
implementation for much faster validation. No longer using Symfony2
Validation component.
[Service] Using an ApiParam object for parameters instead of a Collection object
Only setting the command value when needed
Adding tests for ApiParam
[Common] Optimizing configuration injection.  No longer supporting the {{}} format for configuration injection.  You must use {} from now on.
Fixing typo and fixing type tests
LSD on Factory

Changed `self` to `static` to extending the factory can take advantage of late static binding
Merge pull request #48 from cboden/cs

LSB on Factory
[Service] Adding a Serializable interface to ServiceDescriptions.  Adding a ServiceDescription interface.