fix #6: JavaScript in underscore.string v2.4.0 has been relocated

Cause: esamattis/underscore.string@c3088d4#diff-0fd4ef892d9d4990033701887c2f9bcc

Rationale: esamattis/underscore.string#193

index.html

@@ -12,7 +12,7 @@
 <script src="jq/jquery.scrollTo.min.js"></script>
 <script src="bootstrap/js/bootstrap.js"></script>
 <script src="node_modules/underscore/underscore.js"></script>
-<script src="node_modules/underscore.string/dist/underscore.string.min.js"></script>
+<script src="node_modules/underscore.string/lib/underscore.string.js"></script>
 <script src="node_modules/array.prototype.find/index.js"></script>
 <script>
 _.mixin(_.str.exports());