The window elements are not being correctly cleaned up when clear() is called
or when overwritten by newer SN. Furthermore, the window count member is not being
correctly updated when the insertion of a newer SN overwrites the previous one.
I used the circular_map container to avoid this sort of bugs
This was done so it would work when circular buffer holds other things
that are not unique_pointers. Queue and pop_func had to be made public
to be able to call the pop_func when an SDU is discarded.
* Added ability to discard to dyn_block_queue
* Change way of keeping track of SDUs
* Check nullptr in poping callback. Starting to check for nullptr in RLC read_pdu.
* Adding RLC discard tests
* Clearing PDCP info when RLC discard happens
* Read SDUs until they are no longer nullptr
* Changed discard_if to use template argument