Trim usernames on signup

This only applies to signups. We should also do this on the backend too.

src/cloud.js

@@ -352,7 +352,7 @@ Cloud.prototype.login = function (
 };
 
 Cloud.prototype.signup = function (
-	username,
+    username,
     password,
     passwordRepeat,
     email,
@@ -361,7 +361,7 @@ Cloud.prototype.signup = function (
 ) {
     this.request(
         'POST',
-        '/users/' + encodeURIComponent(username) + '?' + this.encodeDict({
+        '/users/' + encodeURIComponent(username.trim()) + '?' + this.encodeDict({
             email: email,
             password: hex_sha512(password),
             password_repeat: hex_sha512(passwordRepeat)