Make Docs Headings Easily Linkable

[Cassidy James Blaede]

Per bug 1021096, headings should get unique IDs, making them linkable. We should also take this a step further and make it easy to link to the section. Possible solutions would be:

* Clicking a heading would scroll to it and put the URL in the address bar
* Hovering a heading would put a symbolic "link" icon next to it which would copy the unique URL to the user's clipboard

Or something else. :P An interesting example can be found at http://developer.android.com/design/style/iconography.html#action-bar. Clicking a heading scrolls to the section and makes the link appear in the address bar (essentially links to the anchor and uses some js to do the fancy scrolling).