1.  Store the encoding enumeration values in the Translation
    object, instead of the charset table.

2.  Use the encoding.c charset table data instead of the ones
    in translate.c.

3.  Remove the charset language file option -- it is only used
    in the Arabic language file, but is used incorrectly there.

4.  Specify ISO 8859-6 for the 8-bit encoding for Arabic instead
    of UTF-8, so that espeakCHARS_8BIT and espeakCHARS_AUTO work
    correctly for Arabic.