Provides an implementation of McCarthy's `amb` operator with
binding forms and acceptance test operator.

Constraints solving functions that operate on a Constraint Description
which is a map describing a constraint description containing the mappings:
- :variables -> seq of LVars
- :formula -> list describing a predicate expression composed of a mix of
  the LVars in :variables and Clojure functions.

Most functions in rv work off of one or more of the following root
concepts:

- Entity: a hashmap with a :kb/id key mapped to a unique value and namespaced keys
- Table: a set of hashmaps or Entities
- Fact: a vector triple in the form [entity-id attribute value]
- Relation: a set of Facts pertaining to a particular Entity
- LVar: a logic variable that can bind to any value in its :range
- Ground: a concrete value
- Query: a set of Facts containing a mix of LVars and Grounds  
- Rules: a set of Facts describing synthetic relations
- Production: a pair of: antecedent query and consequent Facts
- KB: a set of Relations about many Entities and possibly containing Productions  
- Constraint Description: a set of LVars and a Formula describing the domain of their values
- Formula: a list describing a predicate expression of mixed LVars and clojure functions

A minimal implementation of Datalog.

I came across the Soundex algorithm when researching the retro KAMAS outlining application.
Soundex is a phonetic algorithm for indexing words by sound.

Provides internal unification functions.
DO NOT USE THIS NS.
There is no guarantee that it will remain stable or at all.

The simplest possible production rules system that uses a set
of EAV tuples as its knowledge base.

A* search implementation.