Feature/state transition machine

According to [Travis](https://travis-ci.org/elcodi/elcodi/jobs/42893120#L305), it looks like this is breaking in PHP5.4:

```
PHP Fatal error:  Can't use method return value in write context in 
/home/travis/build/elcodi/elcodi/src/Elcodi/Component/StateTransitionMachine/Machine/MachineBuilder.php on line 359
```
I would change it to

```php
if (!$this->transitionChain->getTransitionsByFinalState($initialStateName)))
```
 Which [is equivalent](http://php.net/manual/en/function.empty.php). 

Iin PHP5.5. this works fine because `empty()` supports [expressions](https://wiki.php.net/rfc/empty_isset_exprs) instead of variables only