Apparently we were reading packed booleans wrong the whole time
(whoops!) They are packed into *bytes*, oops... That is fixed now, and I
also expanded write support for packed booleans. It makes the assumption
that the byte is always at the end of the row, but I think that's OK for
now.
I also added a good test-case for this, the PhysicsGroup EXD. It has a
lot of rows, and some packed booleans thrown in. The columns also have
out-of-order column definitions (as in, their offsets don't increase in
order.)
Expanding upon the EXH tests of this same data, we can successfully
write it back (hence why it's testdata now!) A lot of the writing logic
is specific for this EXD, but it's a start.
Now it reads much more of the index file format, and tries to handle
index1/index2 differences more opaquely. I'm not yet happy with the API, it
needs a bit more work.
