edge: Handle EGPRS PACKET DOWNLINK ACK NACK

Currently this message is ignored.

Support decoding and handling of this message. Use a bitvec for the
decoder that just represents a BSN sequence without any encoding
details (first bit -> first BSN). Return the corresponding BSN range
(snsmod(bsn_begin + bits_in_bitvec) = bsn_end), so snsmod(bsn_end-1)
is the last BSN if there is at least 1. If bsn_begin == bsn_end, no
BSNs has been added.

Note that this bitvec is not yet used for RBB handling. It just calls
the old rcvd_dl_ack with a faked (all bits are 1) RBB map.

Sponsored-by: On-Waves ehf
diff --git a/src/csn1.cpp b/src/csn1.cpp
index 377c50f..54cc411 100644
--- a/src/csn1.cpp
+++ b/src/csn1.cpp
@@ -549,6 +549,7 @@
 
         csnStreamInit(&arT, bit_offset, length);
         arT.direction = 1;
+        LOGPC(DCSN1, LOGL_NOTICE, "ptr = %p | offset = %d | ", (void *)data, (int)pDescr->offset);
         Status = serialize(&arT, vector, readIndex, pvDATA(data, pDescr->offset));
 
         if (Status >= 0)