Add default elytra flying value (#69)

Author: lkwilson

README.md

@@ -126,6 +126,10 @@ The health of the player, default: 20
 
 The food of the player, default: 20
 
+#### entity.elytraFlying
+
+Whether or not the entity is elytra flying.
+
 #### entity.player
 
 The player

index.d.ts

@@ -41,6 +41,7 @@ declare module 'prismarine-entity' {
         health?: number;
         food?: number;
         foodSaturation?: number;
+        elytraFlying?: boolean
         player?: object;
         effects: Effect[];
         setEquipment(index: number, item: Item): void;