Callback: Decide input and output cargo types

Decide input and output cargo types (14B,14C)

These callbacks are called when the industry is built, and allow customizing the input and output cargo types dynamically. Both callbacks are called repeatedly, with the lowest byte of variable 10 starting from zero and increasing after every call; you should return a cargo type each time, or FFh to terminate the list. (A failed callback terminates the list, too.) The same limitations apply as for callback 14A: industry tiles aren't yet placed, and some industry variables contain junk. You can use random action2s, however. The interpretation of the returned value depends on two factors: the current GRF version number and the presence of a cargo translation table:

GRF version	Has cargo translation table	Interpretation
6 or below		Climate-dependent cargo slot number
7 or above	No	Cargo bit
7 or above	Yes	Index in the translation table

Although currently callback 14B is called no more than three times, and callback 14C no more than twice, this may change between versions/implementations, to allow more input/output types. To be safe, you should return FFh as the last element even when you use all three input types or both output types.