Review of porters-handbook changes

[Mark Linimon]

> I tried to preserve the style of adjacent blocks.  To that end, some use
> spaces, so I opted for spaces to keep things lined up.

I did the same with my patches.

At some point when all this stuff gets committed I'll volunteer to do
a whitespace diff on the thing at which time we can settle on the
Right Way and not confuse future contributors.

mcl