DEV 1247: Add a new map generator interface (#71)

* reorganize code

* first draft of map generator interfaces

* add explicit random interface to board helpers

* implement standard map

* rename Generator to GameMap

* allow initializing snakes separately from placing them

* add random number generator to Settings

* updates to GameMap interface

* add helpers for creating and updating BoardState with maps

cli/commands/play.go

@@ -231,7 +231,7 @@ func initializeBoardFromArgs(ruleset rules.Ruleset, snakeStates map[string]Snake
 	for _, snakeState := range snakeStates {
 		snakeIds = append(snakeIds, snakeState.ID)
 	}
-	state, err := rules.CreateDefaultBoardState(Width, Height, snakeIds)
+	state, err := rules.CreateDefaultBoardState(rules.GlobalRand, Width, Height, snakeIds)
 	if err != nil {
 		log.Panic("[PANIC]: Error Initializing Board State")
 	}