Use resolveChannel instead of resolveVoiceChannel for joinVoiceChannel and get rid of resolveVoiceChannel

lib/Client/InternalClient.js

@@ -269,12 +269,11 @@ var InternalClient = (function () {
 	InternalClient.prototype.joinVoiceChannel = function joinVoiceChannel(chann) {
 		var _this3 = this;
 
-		var channel = this.resolver.resolveVoiceChannel(chann);
-
+		return this.resolver.resolveChannel(chann).then(function (channel) {
 			if (!channel) {
 				return Promise.reject(new Error("voice channel does not exist"));
 			}
-		return this.leaveVoiceChannel().then(function () {
+			return _this3.leaveVoiceChannel().then(function () {
 				return new Promise(function (resolve, reject) {
 					var session,
 					    token,
@@ -312,6 +311,7 @@ var InternalClient = (function () {
 					});
 				});
 			});
+		});
 	};
 
 	// def createServer

lib/Client/Resolver/Resolver.js

@@ -236,14 +236,6 @@ var Resolver = (function () {
 		return null;
 	};
 
-	Resolver.prototype.resolveVoiceChannel = function resolveVoiceChannel(resource) {
-		// resolveChannel will also work but this is more apt
-		if (resource instanceof _StructuresVoiceChannel2["default"]) {
-			return resource;
-		}
-		return null;
-	};
-
 	Resolver.prototype.resolveChannel = function resolveChannel(resource) {
 		/*
   	accepts a Message, Channel, Server, String ID, User

src/Client/InternalClient.js

@@ -200,8 +200,7 @@ export default class InternalClient {
 
 	//def joinVoiceChannel
 	joinVoiceChannel(chann) {
-		var channel = this.resolver.resolveVoiceChannel(chann);
-
+		return this.resolver.resolveChannel(chann).then(channel => {
 			if (!channel) {
 				return Promise.reject(new Error("voice channel does not exist"));
 			}
@@ -242,6 +241,7 @@ export default class InternalClient {
 					});
 				});
 			});
+		});
 	}
 
 	// def createServer

src/Client/Resolver/Resolver.js

@@ -166,14 +166,6 @@ export default class Resolver {
 		return null;
 	}
 
-	resolveVoiceChannel(resource) {
-		// resolveChannel will also work but this is more apt
-		if (resource instanceof VoiceChannel) {
-			return resource;
-		}
-		return null;
-	}
-
 	resolveChannel(resource) {
 		/*
 			accepts a Message, Channel, Server, String ID, User