Clear any frame/packet confusion

There was a previous issue about renaming the packets to frames but upon revisiting the code i think there are still some instances where there is some confusion, meaning that the term frame is used where it should be packet and vise versa.

Clear up the variable names and be especially careful about the frame/packet data. In the data link we consider packets the "main" data either TM or TC that we want to transfer. Transfer frames are the packets along with the added headers and trailers.