Add missing comment types to settings (Octave)
Re-organize settings, properly set TM_USE_OCTAVE

Put settings under a single item for each language for readability, enable TM_USE_OCTAVE that is used in some snippets.
Add various Octave specific ending keywords

end_try_catch, endfor, endfunction, endif, endwhile
Add parfor/endparfor keyword

Based on a patch from @cerveza1988