fix(buildQuery): support params without key

closes #243 #383

src/URI.js

@@ -744,7 +744,7 @@
     var t = '';
     var unique, key, i, length;
     for (key in data) {
-      if (hasOwn.call(data, key) && key) {
+      if (hasOwn.call(data, key)) {
         if (isArray(data[key])) {
           unique = {};
           for (i = 0, length = data[key].length; i < length; i++) {

test/test.js

@@ -1321,6 +1321,9 @@
 
     u.query('?&foo=bar&foo=bar').normalizeQuery();
     equal(u.query(), 'foo=bar', 'duplicate key=value resolution');
+
+    u.query('?=bar').normalizeQuery();
+    equal(u.query(), '=bar', 'query without key');
   });
   test('normalizeFragment', function() {
     var u = new URI('http://example.org/foobar.html#');
@@ -1330,6 +1333,9 @@
   test('readable', function() {
     var u = new URI('http://foo:[email protected]/hello%20world/ä.html?foo%5B%5D=b+är#fragment');
     equal(u.readable(), 'http://www.exämple.org/hello world/ä.html?foo[]=b är#fragment', 'readable URL');
+
+    var u = new URI('http://example.org/?=5640');
+    equal(u.readable(), 'http://example.org/?=5640', 'readable URL: query without key');
   });
 
   module('resolving URLs');