M. Eric Irrgang authored Sep 28, 2018 and Mark Abraham committed Oct 03, 2018

The Context holds the details necessary to launch work in a given
environment. A runtime session is launched using the configured details
of a Context implementation and the object bindings configured by the
user (managed by the Context).

Part of a sequence of changes introducing gmxapi classes System,
Context, Session, and Workflow.

Supports gmxapi milestone 5

Refs: #2587

Change-Id: I75baed9b5c856f284bc2c2370ef284319e95f13e