Clean-up the DFUfileformat and separate file 'kind' and 'encoding'

enum DFUfileformat
{
    DFUff_unknown = -1,
    DFUff_fixed,
    DFUff_csv,
    DFUff_utf8,
    DFUff_utf8n,
    DFUff_utf16,
    DFUff_utf16le,
    DFUff_utf16be,
    DFUff_utf32,
    DFUff_utf32le,
    DFUff_utf32be,
    DFUff_variable,
    DFUff_recfmvb,
    DFUff_recfmv,
    DFUff_variablebigendian}; 

and

typedef enum
{
    FFTunknown,
    FFTfixed, FFTvariable, FFTblocked,
    FFTcsv,
    FFTutf,                             // any format, default to utf-8n
    FFTutf8, FFTutf8n,
    FFTutf16, FFTutf16be, FFTutf16le,
    FFTutf32, FFTutf32be, FFTutf32le,
    FFTrecfmvb, FFTrecfmv, FFTvariablebigendian,
    FFTlast
 } FileFormatType;