std::is_pod<> being less restrictive than is_binary_serializable<> meant that
structs that both were POD and had a serialize method defined would be binary
serialized instead of using the defined serialize(). This means that it would
also serialize any padding that the struct contained, which would cause mass
waves of valgrind failures from uninitialized memory.
Included in this change is additional uses of valgrind client requests so that
attempts to send uninitialized memory are reported at the sending site, versus
as part of checksum calculation in sending the packet.
Alec Grieser