Refactor production export rake command.

Removed index_production.html - it goes too easily out of sync.
Instead using index.html as a template where placeholders are
replaced with data optionally passed from command line.  For that
added new options:

  --title - to set the title of page.
  --extjs-path - to use extjs/ext-all.js in production.
  --append-html - to add the analytics code.