Start overhauling execution docs to be actual docs.

Includes ruminations about CLI level parameterization
HERP DERP
Hurr
Meh
Fix pre-task test to be accurate (still passes)
Create failing no-deduping test
Implement basic Task.__call__
Implement call tracking
Re-implement default/deduping behavior in Executor
Reimplement deduping hurr
Cleanup