package: use more accurate terminology (`url` vs `host`)

lib/index.js

@@ -103,7 +103,7 @@ export default class Now extends EventEmitter {
     }, { retries: 3, minTimeout: 2500, onRetry: this._onRetry });
 
     this._id = deployment.deploymentId;
-    this._url = deployment.url;
+    this._host = deployment.url;
     this._missing = deployment.missing || [];
 
     return this._url;
@@ -165,8 +165,16 @@ export default class Now extends EventEmitter {
     this._agent.close();
   }
 
+  get id () {
+    return this._id;
+  }
+
   get url () {
-    return this._url;
+    return `https://${this._host}`;
+  }
+
+  get host () {
+    return this._host;
   }
 
   get syncAmount () {