notes

concepts
   Individual - one genetic program to evaluate and evolve
   Population - a pool of individuals 
   Evolver - TinyGP (the thing that does the evolution, coordinates everything else.
   Selector - selects the best-of or worst-of a generation.  Uses a "Tournament"
     Tournament
   Crossover - Randomly mix two individuals together to produce an offspring
   Mutation - Randomly alter one individual to produce a new offspring
   Fitness - algorithm used to evaluate the worthiness of an individual
   FitnessCase - one dataset used by the fitness algorithm, there should be many.

   Grammar - set of Symbols that a genetic program (the indidividual) can be composed of
     Symbol - The top-level representation of everything in a Grammar.
       Terminal - A end-leaf node that depends on no other sybols (a constant, variable or random value)
         Constant
         Variable
         Random value
       Function - A branch node that depends on n symbols to acheive its calculation.
         Add
         Subtract
         Divide
         ...