Removed class member access on instatiaton

PHP 5.3 doesn't allow accessing a class member (method or property) when
instantiating the class. Moving the `new` keyword to the above line
makes the SDK totally usable in that PHP version.

PHP 5.3 is still used in about 50% of the PHP-powered websites.

![screenshot_36](https://cloud.githubusercontent.com/assets/2876259/2962883/48f841e2-dad5-11e3-9ad7-b564c18315a0.png)