Fix the behaviour of “Trash aux files”

Hi,

this pull request should fix the behaviour of “Trash aux files”. Currently “Trash aux files” does not remove most auxiliary files. It (theoretically) however removes the generated PDF/PS file. This pull request should change this behaviour. We now keep the generated PS/PDF file while we remove the most common auxiliary files. This commit should fix #43 and #83.

Kind regards,
  René