RFE: enhancements for the future of the project

[ankostis]

Collecting here enhancements that would nice to have on this project going forward:

Language & Build

• 1.1 (ENH: Preparations for releasing v1.3.0 #30) Black-en
• 1.2 drop PY2 (EOL this year)
  • 1.3 Proper use of named-kwargs
  • 1.3.1 f-strings
  • 1.3.2 type annotations
• 1.4 drop <PY3.6
• (FEAT: ExecutionPlan remember compilation results for elaborate plots #29) 1.5 use logging module instead of print()
• 1.6 (ENH: use pytest instead of numpy for tests #28) pytest fixtures and parametrization
• 1.7(ENH: Preparations for releasing v1.3.0 #30) add API reference & link to RTD generated docs in github's project description.
• restructure a better roles for modules base & functional.

Functionality

• 2.1 drop "backward compatibility" Operation, clean up API
  (e.g. FunctionalOperation.compute() raises not impl, and network using private _compute() instead).
• 2.2 (ENH: annotate graph edges as optionals #20) store node data in networkx and not in classes
• 2.3 add weights
• 2.4 produce deterministic results & failures:
  • 2.4.1 use ordered-dicts (dicts are insertion-ordered in PY3.6+)
  • 2.4.2 (FIX: use insertion-ordered sets for deterministic results #23) use ordered-sets, or sort them prior to iterating them
  • 2.4.3 (FEAT: ExecutionPlan remember compilation results for elaborate plots #29) use ordered networkx.DiGraph.
• 2.5 support optional outputs.
• 2.6 support combination of modifiers (e.g. optional-sideffect).
• 2.7 assign "colors" to operations, and compute selectively on sub-sets of colors (idea from @syamajala's https://github.com/slac-lcls/networkfox)
• 2.8 parallel executor must accept an external "shared" pool (now uses the one from Network).