Digiline filter injectors can send mixed items when only `count` is specified.

e.g. 1) digiline filter injector ejecting from autocrafter making RE-batteries. Sending { count = 8 } to the injector causes 8 batteries to move (8 stacks of one).

e.g. 2) have 3 stacks in a chest each with 10 items but 3 different materials (iron, copper, silver dust). Sending { count = 30 } to the injector causes all three stacks to move.

This breaks common standard of one stack per event. Causing issues with detector tubes, lua-tubes etc.

For example a grind/smelting setup may have lumps/dust of various materials in a chest and instructing filter to inject 33 items at a time into grinder/furnace can cause multiple stacks to bounce back. Not a big problem to the user if chest, injector and machine are directly adjacent. However it causes unnecesary overhead for the server and can break calculations the user is doing with detector tubes to keep track of input.

Noticed since #167 was merged.