BinaryHuffmanTree: explicitly provide '=default'ed constructor, maybe appeases clang-3.5?
BinaryHuffmanTree: explicitly provide '=default'ed constructor, maybe appeases clang-3.5?

LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed