Provide parameters for hardcoded English text

[peterdesmet]

• [ ] home.html: Tweets by
• [ ] default.html: On this page
• [x] default.html: Please enable JavaScript to view the comments powered by Disqus. Leave as is, warning message
• [ ] card.html: alt = Background image Leave as is
• [x] footer.html: © Leave as is
• [ ] footer.html: Edit this page
• [x] head.html: title = RSS feed - ... Leave as is
• [x] header.html: date format '%B %d, %Y' (in English) Hard to change without a locale setting
• [ ] header.html: Image by
• [ ] navbar.html: Menu