Move fsockopen out of constructor

First, thanks for this repo.  I've made a small change to where the ```fsockopen``` call is being made.  In testing environments (e.g. Travis) where there is no expectation of having a gearman server to connect to, calling ```fsockopen``` within the constructor was problematic.  Instead, this has been moved to a ```connect()``` method that is called before the connections are needed.