Update README and example to use /index.html not /
More flexible match of navbar list items. Fixes #39.
When no Pygments, return (listof xexpr?) not string? Fixes #38.
Better comments.
Define two functions instead of using case-lambda.
Rewrite xexpr->markdown
Infer non-post page title from h1. Closes #40.
Polish commit 45e79c74. Add unit test for nested bold in italic.
Require markdown 0.3. Fixes #41.
Require markdown 0.4. Correctly fixes #41.
Move some code to new files.

Part of ongoing process to get frog.rkt well under 1,000 LOC.
Add/use `cached-file`.

Generalized function for what `read-navbar` was doing.
Major redesign leveraging `web-server/templates`.
Delete obsolete section of README missed in prior commit.
Fix indent
Pass `full-uri` as a value, not a function
Clean up page-template.html

- Be careful not to use @vars in HTML comments.
- OK to use `when` instead of `if`: void = "".
- Indents.
Change a comment.
Use for in-dict instead of hash-map
Use xexpr->string/pretty