Pharmaceutical composition for use in the treatment of irritable bowel syndrome, diarrhea, constipation, abdominal pain and / or abdominal swelling or bloating in a mammal, use of one or more vanilloid compounds, their pharmaceutically acceptable salts, analogs and derivatives, and processes for the treatment of irritable bowel syndrome, diarrhea, constipation, abdominal pain and / or abdominal swelling or distension of a mammal and for the manufacture of a composition