Comparison of multidimensional associative arrays

[Alexander Zhirov via Digitalmars-d-learn]

Not an easy task for me, maybe you can advise your compact 
solution. There are two associative arrays of type 
`string[string][int]`. It is necessary to find the differences 
and return them when comparing:

```d
[
    6:["id":"6", "deleted":"f", "name":"6.2_test"],
    5:["id":"5", "deleted":"f", "name":"5.6_test"],
    4:["id":"4", "deleted":"f", "name":"6.2_hwlister"],
    3:["id":"3", "deleted":"f", "name":"5.6_hwlister"],
    2:["id":"2", "deleted":"f", "name":"6.2"],
    1:["id":"1", "deleted":"f", "name":"5.6"]
]
[
    4:["id":"4", "deleted":"f", "name":"6.2_hwlister"],
    3:["id":"3", "deleted":"f", "name":"5.6_hwlister"],
    2:["id":"2", "deleted":"f", "name":"6.2"],
    1:["id":"1", "deleted":"f", "name":"5.6"]
]
```