Merge pull request #5510

a0ae79d Replace CBlockHeader::GetHash with call to SerializeHash (Wladimir J. van der Laan)
62b30f0 Add serialize float/double tests (Wladimir J. van der Laan)
9f4fac9 src/txmempool.cpp: make numEntries a uint32_t (Wladimir J. van der Laan)
f4e6487 src/arith_256.cpp: bigendian compatibility (Wladimir J. van der Laan)
aac3205 src/netbase.h: Fix endian in CNetAddr serialization (Wladimir J. van der Laan)
01f9c34 src/serialize.h: base serialization level endianness neutrality (Wladimir J. van der Laan)
4e853aa src/script/script.h: endian compatibility for PUSHDATA sizes (Wladimir J. van der Laan)
4f92773 src/primitives/transaction.h: endian compatibility in serialization (Wladimir J. van der Laan)
81aeb28 src/primitives/block.cpp: endian compatibility in GetHash (Wladimir J. van der Laan)
dec84ca src/net.cpp: endian compatibility in EndMessage (Wladimir J. van der Laan)
556814e src/main.cpp: endian compatibility in packet checksum check (Wladimir J. van der Laan)
3ca5852 src/hash.cpp: endian compatibility (Wladimir J. van der Laan)
4414f5f build: Endian compatibility (Wladimir J. van der Laan)