DF/data4es-nested: port data4es DF changes made in PR #284.

[mgolosova]

095 update: part 2.

Query improvements:

• use -scope parameter to get data for datasets in non-default scope;
• do not query AMI for datasets beyond AMI's scopes ('mc15', 'mc16');
• use normalized DS name in the query.

[mgolosova]

@Evildoor,
As it was promised, your PR #284 is ported to the "nested" version of the dataflow (for the PR had been created before the "nested" DF landed to master).
From now on, please remember that all the improvements are to be done in this "nested" DF, not the original data4es (except for hotfixes, which are to be made in both DFs).