Fix PATCH with nested fields

[finrod2002]

This fixes an issue where PATCH requests with add operation and no path field containing nested fields (with '.') where not correctly applied.

For example the following PATCH request:

{
    "Operations": [
        {
            "op": "replace",
            "value": {
                "name.familyName": "test",
                "name.formatted": "test test2"
            }
        }
    ],
    "schemas": [
        "urn:ietf:params:scim:api:messages:2.0:PatchOp"
    ]
}

wasn't correctly applied. See issue #224 for more details.

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What does this implement/fix? Explain your changes.

This pull request fixes #224. I'm sure the code can be greatly improved. Anyway, I needed a quick fix to be able to go on with my project and I thought it would be nice to share it. Unfortunately, I have not the time to improve it further at this moment.

Does this close any currently open issues?

It would close #224. Please see notes above about the code.