Fix attribute read for values nested on multiple levels

[bstanescu]

There is a bug in the retrieval of intermediary nested values
Let's assume the following structure of data:
$foo['a.b.c'] = 1;

>>> $foo['a'];
=> [
     "b" => [
       "c" => 1,
     ],
   ]

>>> $foo['a.b'];
=> null // <-- this is wrong as it should return this:

>>> $foo['a']['b'];
=> [
     "c" => 1,
   ]

>>> $foo['a.b.c'];  // this works fine
=> 1

[jenssegers]

Could you still use the if that checks if the key contains a dot? So that we still use the parent logic in any other case.

[bstanescu]

Good point (pun intended 😄 ). Done.