Dedent python code blocks

Dedent python code blocks.
Removed rewrite links and 'base_url'

Deleted markdown extension MarkdownRewriteLink and associated
RewriteLinkExtension, and variable `defaults[‘base_url’]` since its
functionality is provided by tag `<base>` and `{{home_link}}`
Remove rewritelinks from the private extensions
removed temp config
xx
Merge branch 'Minus-Rewrite-links'
Added --server command line option

now, the command line —server will build the site and start a
simpleHTTPServer in the build directory.
little changes