Always use RFC3339 for version date format.

Fixes #695 reported by @synful.

- No longer tries to load a configuration.
- Because of this the version tests are no longer necessary.
Remove Println that panics in test
Correct URL of the favicon in the documentation

img/favicon.png does not seem to exist,
so follow the example in docs/layouts/index.html
and use /favicon.ico instead.
Docs: Quote <!--more--> in <code> instead of italicizing it

Also replace "--" with "&#x2d;&#x2d;" prevent "--" from
being interpreted as en-dash.

Note: A simple `<!--more-->` does not work.
Docs: Minor copyediting/proofreading

- Correct some typos
- Add backticks and commas where necessary
- Use fenced code blocks specifying "bash" as the language
  to avoid weird highlighting
- Place commas outside of quotation marks surroundingn codes
  to avoid possible confusion
- Suggest users to use the discussion forum rather than the
  mailing list
Fix front matter for 'Creating a New Theme'

There seems to be an issue with TOML and certain menu structures. Current workaround: YAML.
Add an `install` target to Makefile.
Add timezone to buildDate
Fix various Windows-issues

File handling was broken on Windows. This commit contains a revision of the path handling with separation of file paths and urls where needed.

There may be remaining issues and there may be better ways to do this, but it is easier to start that refactoring job with a set of passing tests.

Fixes #687
Fixes #660