add support for v2 hashing algorithm.

update README.md and demo file to be more in sync.
update to v0.10.0.

public/demo/hashTwt-example-source.js

@@ -15,18 +15,23 @@ formatSource(
 
                 const content = formHash.elements["content"].value;
                 const created = formHash.elements["created"].value;
+                const version = parseInt(formHash.elements["version"].value, 10);
                 const url = formHash.elements["url"].value;
 
-                const hash = hashTwt({
-                    content,
-                    created,
-                    url,
-                });
+                const hash = hashTwt(
+                    {
+                        content,
+                        created,
+                        url,
+                    },
+                    version,
+                );
 
                 const result = [
                     \`content: \${content}\`,
                     \`created: \${created}\`,
                     \`url: \${url}\`,
+                    \`version: \${version}\`,
                     \`hash: \${hash}\`,
                 ].join("\\n");