Allow whitespace before language type
Allow option to process other languages as raw cells
Fix bug where trailing prose block is lost
Refactor branches of mdjup section processor slightly
Further refactoring on mdjup
Merge branch 'mdjup-fix' into develop

* mdjup-fix:
  Further refactoring on mdjup
  Refactor branches of mdjup section processor slightly
  Fix bug where trailing prose block is lost
  Allow option to process other languages as raw cells
  Allow whitespace before language type