Adding a command.after_prepare event
Adding number types to service description schemas. Closes #265.
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).
Adding ability to overwrite config params for throw-away clients in the service builder
Updating the docblock of the ServiceBuilderInterface::get method to allow for arrays
Adding support for additionalProperties for parameters in service descriptions. Addresses #270
Renaming additionalProperties to additionalParameters
Removing requirement on PHP 5.3.7 for checking ResponseClassInterface. Closes #293