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
Indent
Add UPGRADE.md to help people upgrading from 0.2
Version 0.3
Edit UPGRADE.md
Link to web-server/templates doc page
Add missing reference link defn
Add --init command to create new project
Many README edits, including using --init
Misc more README edits.
More README edits
Improve command line help
More README edits, especially templates.