Fix TypeScript building issues

Includes definitions fix for instance properties.

src/components/CharacterDisplay.vue

@@ -13,7 +13,7 @@ import Character from '../models/Character';
 @Component
 export default class CharacterDisplay extends Vue {
 	@Prop() character!: Character;
-	healthText: string;
+	healthText = '';
 
 	created() {
 		this.healthText = `Health: ${this.character.currentHealth} of ${this.character.baseStats.health}`;

src/components/HelloWorld.vue

@@ -99,7 +99,7 @@
 
 <script lang="ts">
 import { Component, Prop, Vue } from 'vue-property-decorator';
-import PartyDisplay from './PartyDisplay';
+import PartyDisplay from './PartyDisplay.vue';
 import { DiceRoll, DiceRoller } from 'rpg-dice-roller';
 import World from '../models/World';
 import Character from '../models/Character';
@@ -297,9 +297,9 @@ export default class HelloWorld extends Vue {
 		currentHealth: 10
 	};
 
-	let roll: DiceRoll | DiceRoll[];
-	let damageRoll: DiceRoll | DiceRoll[];
-	let dodgeRoll: DiceRoll | DiceRoll[];
+	let roll: DiceRoll;
+	let damageRoll: DiceRoll;
+	let dodgeRoll: DiceRoll;
 	let currentCharacter = 0;
 	let nextCharacter = 1;
 	let damageTotal = 0;

src/components/PartyDisplay.vue

@@ -21,7 +21,7 @@
 
 <script lang="ts">
 import { Component, Prop, Vue } from 'vue-property-decorator';
-import CharacterDisplay from './CharacterDisplay';
+import CharacterDisplay from './CharacterDisplay.vue';
 import Party from '../models/Party';
 import { partyStateToText } from '../utilities/Enums'
 @Component({
@@ -32,7 +32,7 @@ import { partyStateToText } from '../utilities/Enums'
 
 export default class PartyDisplay extends Vue {
 	@Prop() private party!: Party;
-	partyHeading: string;
+	partyHeading ='';
 	stateText = '';
 
 	created() {

src/testWorld.d.ts

@@ -0,0 +1,9 @@
+import Vue from 'vue';
+import World from './models/World';
+
+declare module 'vue/types/vue' {
+	interface Vue {
+		$world: World;
+		$testWorld: World;
+	}
+}