Changes to EventStore connection failure handling

Looking for feedback. Thanks again for working on an EventStore php client!

The goal here is to save an additional request each time I load up EventStore and to move the connection exception into the first sendRequest() that is called.

This also provides a way to configure timeout settings for connect/request. Obviously the defaults are not well thought out but I sure wouldn't wait more than 2 seconds for a "local" EventStore :)

Thanks!
This calls for a Configuration value object, @nicolopignatelli what do you think about it?