Built the body of `index.jsp`.

* Made `View.getAuthorLink` and `View.getUserName` into static methods
because they don’t access any members of the `ContentsView` instance.
* Reformatted the welcome text so that it didn’t display too wide.
* Added the body of the table of contents.
* Added functions to the `View`, `ContentsView`, and `StoryBeginning`
to help the gathering of the story titles.
* Added a link for starting a new story.
* Added links for auxiliary pages such as “About” and “Contact”.
The index page now displays page numbers for the displayed stories.