Improve "[PARAM] is a required [TYPE]" message

This happens when Guzzle is trying to create an error message of the
form "ID is a required integer", but the type is an array (union) of
types rather than a single type in a string.

In PHP 5.4, this causes a notice "array to string conversion", and in
all versions of PHP, the message Guzzle generated reads "ID is a
required Array" (where "Array" is the result of the array-to-string
conversion, almost always not what you want).
Merge pull request #272 from bradfeehan/improve-require-message

Improve "[PARAM] is a required [TYPE]" message
Adding ability to overwrite config params for throw-away clients in the service builder
Merge pull request #273 from jeremeamia/master

Overwrite config params for throw-away clients in the service builder
Updating the docblock of the ServiceBuilderInterface::get method to allow for arrays
Merge pull request #274 from jeremeamia/master

Updating the interface docblock for the previous ServiceBuilder change
Adding support for oauth_callback parameter.
Merge pull request #275 from fubhy/master

Add support for 'oauth_callback' parameter.
Adding callback parameter to constructor docblock.
Merge pull request #276 from fubhy/master

Fix missing 'callback' parameter documentation in constructor docblock.
Adding the ability to create a custom stream class from a stream factory
You can now send any EntityEnclosingRequest with POST fields or POST
files and cURL will handle creating bodies
* Lots of cleanup to CurlHandle::factory and RequestFactory::createRequest
* POST requests using a custom entity body are now treated exactly like PUT
requests but with a custom cURL method. This means that the redirect
behavior of POST requests with custom bodies will not be the same as POST
requests that use POST fields or files (the latter is only used when
emulating a form POST in the browser).
* Closes #266
Adding the ability to PURGE requests from the cache. Addresses #241.
Adding pem to PEAR package. Addresses #280.
Adding cacert file to phar and more cert validation
Addresses #280.
Updating to curl's latest cacert file
Using copied cacert when using phar
typo
Merge pull request #282 from DarkSide666/master

typo
Adding a caching entity body decorator and cleaning up other entity body decorators