Fix frontmatter parsing changes from #1608
Fix frontmatter parsing changes from #1608

Only allow frontmatter at the top of the page:
  Now manually removing encoding lines as before

Fix handling of postscript data:
  If there is no frontmatter and the filetype is known,
  parse the whole file

Allow empty frontmatter

Update the documentation comments

mvastola/middleman,mvastola/middleman,middleman/middleman,mvastola/middleman,puyo/middleman,middleman/middleman,mvastola/middleman,mojavelinux/middleman,puyo/middleman,mojavelinux/middleman,puyo/middleman,mojavelinux/middleman,middleman/middleman,mojavelinux/middleman,puyo/middleman,middleman/middleman