Support for numbers in box texts.

Worked on readme file

test/web.html

@@ -43,7 +43,7 @@
     </div>
     <div class="mermaid">
         graph TD;
-            eag[Läsa bok]-->b;
+            eag[Läsa bok 2]-->b;
             b{Fundera}---|Klocka|c(Vidar);
             b-->|Lego text|d(Bjarke går);
             e(orphan);
@@ -51,6 +51,10 @@
             style eag fill:#6ff,stroke:#f66,stroke-width:2px,stroke-dasharray: 5, 5;
             style #2 stroke:#0f0;
     </div>
+    <div class="mermaid">
+        graph LR;
+        A---|This is the text|B;
+    </div>
     <script src="../dist/mermaid.full.js"></script>
     </body>
 </html>