Merge pull request #7 from juannorris/fix/nil-left-hand

Use Null ValueNode instead of nil on allowUndefinedFacts

Create CODE_OF_CONDUCT.md

refactor package

refactor package

Merge pull request #6 from nimbit-software/feature/rework-almanac+operators

Refactor entire engine

update benchmark

rework-almanac+operators

fix tests

alter tests and add more strongly typed interfaces

Merge pull request #4 from juannorris/fix/set-priority

add stronger rule types

Fix setting a priority on Rule and stardize parsing priority from input

fix example in README.md