Use SOQL relationship syntax for Salesforce object queries

When loading data for a child object in a parent query (e.g.: loading opportunities with Account.Name child values), two separate SOQL queries are currently generated (with independent series of REST API calls), one for the parent and one for the child. Network traffic and overall payload size would both be considerably reduced if the relationship syntax described at https://developer.salesforce.com/docs/atlas.en-us.204.0.soql_sosl.meta/soql_sosl/sforce_api_calls_soql_relationships_understanding.htm were supported.