Two more aliases for gconv-modules

[Bruno Haible]

Two more aliases could be added to the gconv-modules file.

 * ISO-8859-14, new alias ISO-IR-199
   (source: http://www.egt.ie/standards/iso8859/8859-14-en.pdf
    page 6 section 7.3)

 * ISO-8859-15, new alias ISO-IR-203
   (source: http://www.egt.ie/standards/iso8859/8859-15-en.pdf
    page 6 section 7.3)

Bruno