The stacks() function and the linknether() and linkoverworld() function

[grinheckerdev]

the stacks function will have 2 arguments (possibly through a decimal point) count, and stack_size (default 64): it should return two values: round(count/stack_size) and count-round(count/stack_size)* stack_size (aka count mod stack_size). It is useful to calculate the amount of stacks of a given amount of items.
Examples:
stacks(159) = (2; 31) (or = 2.31)
stacks(53, 16) = (3; 5) (or = 3.5)

the linkoverworld(x, z) and linknether(x, z) allow you to calculate the coordinates to link a portal.
linkoverworld(x, z) = (x*8 ; z*8) coordinates of a portal in the overworld by the nether coordinates
linknether(x, z) = (x/8 ; z/8) coordinates of a portal in the nether by the overworld coordinates

[grinheckerdev]

Might even do a PR, if I'll have time