Fix for 'ISO C++ says that these are ambiguous' compilation error 

In the Wire library there are 2 methods named Wire.requestFrom(address, quantity). They are: 

Wire.requestFrom(int, int)
Wire.requestFrom(uint8_t, uint8_t)

The previous code was specifying Wire.requestFrom(uint8_t, int) so the compiler doesn't know which of the above methods to use, hence the 'ambiguous' error. I have added a cast to uint8_t to solve this problem.