Add support for array of objects as reference

[flip111]

Could not start test from working test code, see #142

Why is this useful? Consider model relations:
A OneToMany B OneToMany C (a tree)
When creating the entities for B, it's easy to grab that one A. However when creating fixtures for C there are now multiple B's, they clearly belong together (are part of the same A), but they can't be grouped. The only alternative is to do addReference('B1', $Bs[0]); addReference('B2', $Bs[1]); etc

[stof]

object is not a valid typehint in PHP

[flip111]

setting multiple references for a single name does not make sense

@stof please motivate your answer, i shall edit the first post to motivate my PR

[stof]

invalid PHP 5.3 code

[stof]

@flip111 the goal of the ReferenceRepository is to keep a reference to a managed entity to share it between fixtures ("managed" being the reason why we need some logic for it). Having 2 different meaning for the reference seems weird to me.

Thus, even the naming is confusing: setting a reference to an arrya is done with setReferences in your code, which is telling it is registering many references, not one. And then, you still get it with getReference. This is a clear way to see that even for you, the meaning of a reference is not clear anymore

[flip111]

@stof i agree with what you are saying. However i was too afraid to adjust more code then i already have and come up with new names for "reference". Anyway if you or anyone else agrees that the use case is there and validates a change then we can discuss a possible solution to this problem.

Right now it's up to the programmer to remember if a single reference is a reference to an object or an array of objects. But actually i think the setReference method should detect if the $references is an array and then the setReferences method can be removed.

By the way, didn't know this lib had to be compatible with php 5.3