#715 HTML codegen: fix and improve print declarations and logging

• Best to review per commit.
• Fixes:
  • Fixed handling of print declaration stdout/stderr/file targets, with red coloring for stderr in HTML log panel. No coloring for browser console logging.
  • Fixed string escaping, for among others: log output, certain runtime errors, and state printing.
  • Fixed HTML-escaping for logging to log panel.
  • Fixed a CSS style with invalid property value (not end user visible): display does not support visible as value. Changed to inherit as counterpart of none.
• Improvements:
  • Reduced HTML log panel horizontal margin.
  • Use Unix newline for log panel, not Windows newlines. The \r is not needed.
  • Improved empty line logging output. Now: after everything is printed for initial state, and after everything is printed for a transition.
  • Introduced variables to control printing state/transition output (enable or disable it).
  • Updated/extended JavaScript code generation documentation.

Addresses #715