Added the function FT_Read_Fields, it acts as a
finite-state automata to load large TrueType tables
in object structures.
This is experimental, don't mess too much with it,
thanks :-)
fixed another small bug in the FT_Read_xxxx functions
(they didn't updated the stream position in the case of
disk-based streams. This went un-noticed under Linux
which uses memory-mapped files by default)