Allow multiple commands, program calls, etc., to be sent at once

[alanseiden]

This will improve performance for multiple calls, but more important, allow environmental set-ups to be done in the same request as a follow-up program call when using HTTP REST interface, which is truly stateless, and thus needs all setup logic (library list, classpath, etc.) to be done in a single request.

Send multiple program calls or commands in one request to XMLSERVICE. We already support this for commands alone but not programs.

• Improve speed when send multiple program calls, such as CL to set libl and then RPG
  

• Need this for REST/HTTP (such as from Bluemix). Enables multiple operations under a single environment (e.g. library lists).
  

• Node.js and Python already have this
  

[alanseiden]

Pay special attention to the coordination of input calls with their respective output payloads.

[alanseiden]

Evaluate for 2.0 but, if necessary, delay till 2.1.