feat(context): add BindQuery func (#1029)

* feat(context): add BindQuery func, only parse/bind the query string params.

* docs(readme): add BindQuery section.

* docs(readme): fix import.

* docs(readme): separate import

binding/query.go

@@ -0,0 +1,23 @@
+// Copyright 2017 Manu Martinez-Almeida.  All rights reserved.
+// Use of this source code is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package binding
+
+import (
+	"net/http"
+)
+
+type queryBinding struct{}
+
+func (queryBinding) Name() string {
+	return "query"
+}
+
+func (queryBinding) Bind(req *http.Request, obj interface{}) error {
+	values := req.URL.Query()
+	if err := mapForm(obj, values); err != nil {
+		return err
+	}
+	return validate(obj)
+}