Added convenience methods getPlayersManager() and getIslandsManager()

This just helps make the API more friendly and consistent with other
manager getters.

src/main/java/world/bentobox/bentobox/BentoBox.java

@@ -316,21 +316,41 @@ public class BentoBox extends JavaPlugin {
     }
 
     /**
-     * Returns the player database
+     * Returns the player manager
-     * @return the player database
+     * @return the player manager
+     * @see #getPlayersManager()
      */
     public PlayersManager getPlayers() {
         return playersManager;
     }
 
     /**
-     * Returns the island database
+     * Returns the player manager
-     * @return the island database
+     * @return the player manager
+     * @see #getPlayers()
+     */
+    public PlayersManager getPlayersManager() {
+        return playersManager;
+    }
+
+    /**
+     * Returns the island manager
+     * @return the island manager
+     * @see #getIslandsManager()
      */
     public IslandsManager getIslands() {
         return islandsManager;
     }
 
+    /**
+     * Returns the island manager
+     * @return the island manager
+     * @see #getIslands()
+     */
+    public IslandsManager getIslandsManager() {
+        return islandsManager;
+    }
+
     private static void setInstance(BentoBox plugin) {
         BentoBox.instance = plugin;
     }