Fix errors using GetComponents with an interface

[shayded-exe]

Now uses the non-generic version of GetComponents then casts back to the
proper type.

[shayded-exe]

Actually this doesn't quite work right. The GetComponents are returning null. Will update with a real fix.

[shayded-exe]

Aaaand there we go. The cast is now done per-element using Array.ConvertAll. The old method would just cast the whole thing.

[shayded-exe]

I've extracted out the extra code around GetComponents to an extension method.

I wont put it in the pull request, but you can use it if you wish :)

public static T[] GetInterfaceComponents<T>(this Component parent) where T : class
{
    return System.Array.ConvertAll(parent.GetComponents(typeof(T)), c => c as T);
}

[prime31]

I am not sure I am following this. GetComponents works fine with interfaces as of Unity 4.6

From the release notes:
Added smart-allocating GetComponents method which fetches components of type T and grows the list as needed. Non-generic version that supports interfaces has also been added.

[shayded-exe]

Strange, your normal code didn't compile for me because of GetComponents, so that's why I did this. I'm using 4.6.7.