Handle quoted strings in data url (#84)

* handle quoted strings in data url

* unrefactor

* update package json

* Revert "update package json"

This reverts commit 9446109b0f94d9e569a961642f1e57b1a67793ee.

* change background-image to border-image

test/css/style.css

@@ -1,6 +1,7 @@
 body {
   margin: 0;
   background: url('../a.jpg');
+  border-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" x="0px" y="0px" viewBox="0 0 256 256"><g><g><polygon points="79.093,0 48.907,30.187 146.72,128 48.907,225.813 79.093,256 207.093,128"/></g></g></svg>');
 }
 p {
   color: red;