iRectangle2D: don't take trivial types by rvalue-ref
iRectangle2D: don't take trivial types by rvalue-ref

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