Defines `fpp_t` and `f_cnt_t` to be of `size_t` within `lmms_basics.h`. Most of the codebase used `fpp_t` to represent the size of an array of sample frames, which is incorrect, given that `fpp_t` was only 16 bits when sizes greater than 32767 are very possible. `f_cnt_t` was defined as `size_t` as well for consistency.
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Co-authored-by: Dominic Clark <mrdomclark@gmail.com>