Add "use strict" to workload files.
Use named function expressions.
Actually assert that database was dropped.
Use drop_utils.js helpers in renameCollection workloads.
Give teardown function a name in renameCollection workloads.
Move parseConfig() function to separate file.
Create JS class representing a cluster.
Start major refactor of runner.js.
Create a ThreadManager class for spawning and joining threads.
Integrate ThreadManager class into runner.js.
Move extendWorkload() function into separate file.
Make remaining functions private within runner object.
Make changes based on CR comments.