Implement the I2C block transactions on VIA chips which support them:
VT82C686B, VT8233, VT8233A, VT8235 and VT8237R. This speeds up EEPROM
accesses by a factor 10 or so.
I would like to thank Antonino A. Daplas, Hinko Kocevar, Salah Coronya
and Andreas Henriksson for their help in testing this new feature.