Improve token "Bot" removal

src/client/rest/RESTMethods.js

@@ -15,7 +15,7 @@ class RESTMethods {
   }
 
   loginToken(token = this.rest.client.token) {
-    token = token.replace('Bot ', '');
+    token = token.replace(/^Bot /, '');
     return new Promise((resolve, reject) => {
       this.rest.client.manager.connectToWebSocket(token, resolve, reject);
     });

src/sharding/ShardingManager.js

@@ -72,7 +72,7 @@ class ShardingManager extends EventEmitter {
      * Token to use for obtaining the automatic shard count, and passing to shards
      * @type {?string}
      */
-    this.token = options.token;
+    this.token = options.token ? options.token.replace(/^Bot /, '') : null;
 
     /**
      * A collection of shards that this manager has spawned

src/util/GetRecommendedShards.js

@@ -10,7 +10,7 @@ module.exports = function getRecommendedShards(token) {
   return new Promise((resolve, reject) => {
     if (!token) throw new Error('A token must be provided.');
     superagent.get(botGateway)
-      .set('Authorization', `Bot ${token.replace('Bot ', '')}`)
+      .set('Authorization', `Bot ${token.replace(/^Bot /, '')}`)
       .end((err, res) => {
         if (err) reject(err);
         resolve(res.body.shards);