Re #7424. Put 32 bit member variables next to each other.

This saves 8 bytes per object padding with gcc (which seems to ignore
the packing pragma) and will allow me to turn off the packing for the
intel compiler (which gives an avalanche of warnings) without any
effect.
Re #7424. Turn of packing for the Intel compiler.

With the present set of member variables it makes no difference and,
for the most recent compiler version, leads to a warning every time the
header is included (which is a lot!).
N.B. The packing also has no effect with gcc but I've left it on there.
Re #7424. Tidy-ups. No functional changes.
Re #7424. Turn off packing for the Intel compiler.

With the present set of member variables it makes no difference and,
for the most recent compiler version, leads to a warning every time the
header is included (which is a lot!).
N.B. The packing also has no effect with gcc but I've left it on there.
Re #7424. Turn off packing for the Intel compiler.

It makes no difference and gives a warning. (N.B. there's no difference
with gcc either, only visual c++.)
Re #7424. Tidy-ups. No functional changes.