Add ORDER BY selecting for clients

[visill]

No description provided.

[reshke]

general coding done ok.
however test needed here. You can use mock generator to get one

[Denchick]

What happens if the result is very large (for example, several hundred million rows) and does not fit into the router's memory?

There is 2 options here:

• do not crash and produce correct result (any ideas how?)
• return an error or explicitly somehow report that the response is too large

And we need tests for extremely large response situation.

[visill]

@Denchick 1) https://stackoverflow.com/questions/30577308/golang-cannot-recover-from-out-of-memory-crash we cant

[visill]

#753