URL Encode State Hash

You'll notice a mild asymmetry in how hash was
saved vs retrieved.

The retrieval was:
    JSON.parse(decodeUrlComponent(hash))

The save was:
    JSON.stringify(hash)

I modified it to:
    JSON.stringify(encodeUrlComponent(hash))

The reason I noticed this is in one of my apps,
I wanted to be able to copy/share a stateful filter URL.

However without the url encoding, those auto-parsers
of URLs were missing the full filter.

TESTING CONDUCTED:
1. Updated the Hash unit tests to both parse the
   encoded string, as well as generate it.

2. Ran "grunt", which has built/tested/jslinted
   the code.

src/modules/hash.js

@@ -4,6 +4,7 @@ import {root} from '../root';
 const JSON = root.JSON;
 const location = root.location;
 const decodeURIComponent = root.decodeURIComponent;
+const encodeURIComponent = root.encodeURIComponent;
 
 /**
  * Checks if browser has onhashchange event
@@ -75,7 +76,7 @@ export class Hash {
      * @param {State} state Instance of State
      */
     update(state) {
-        let hash = `#${JSON.stringify(state)}`;
+        let hash = `#${encodeURIComponent(JSON.stringify(state))}`;
         if (this.lastHash === hash) {
             return;
         }