Adding new query methods?

[paulandroshchuk]

I just have an idea to add two new methods to allow generating SLIMIT and SOFFSET query clauses.
Just something like this: $client->slimit('tag'), $client->soffset()

Yes, I could use something like this: $client->query(... **SLIMIT**), but I think that it could be a good option to add those two methods.

Let me know if you'd like to have those methods added, I could create a PR for that.