L2SS-244: Return a scalar if given a scalar

(cherry picked from commit 68b98aa8)

L2SS-244: Cannot just link to the client in the class! needs to be looked up during device initialisation!

L2SS-244: Rewrite of StatisticsPacket class: unpack everything in 1 go for efficiency, and split off specialistic SST/XST/BST classes

L2SS-244: Return a max datetime in case of parse issues, not a min datetime which also indicates zeroes

L2SS-244: Don't go overly complex if we need a new buffer every time anyway. Just return a set of bytes for each packet.

L2SS-244: Don't go overly complex if we need a new buffer every time anyway. Just return a set of bytes for each packet.

L2SS-244: Add calculator for what the packet size should be, which helps feeding them from a continuous datastream (like disk).

L2SS-244: Renamed SST->SST_collector to avoid name clashes elsewhere. Expose all collected values in our SST device