This ensures that we can't overflow when adding `pql.Decimal`s together. The
only place we can possibly overflow is when converting pql.Decimal to an Int64,
but that is a risk we have to take. Also, the only place we do this is in our
ToRowser. We could maybe change that to strings, so the presentation of data
doesn't indicate an overflow, but that is a later decision to make. It will
also involve fixing the generate-proto-grpc make command, because that's broken
rn.
i used this script, a little clunky but it got the job done
```bash
for file in `find . -type f -print | grep '\.go'`; do
sed '1,/^\/\/ limitations under the License.$/d' $file > $file.tmp;
result=`cat $file.tmp`
if [[ result != "" ]]; then
gofmt $file.tmp &> /dev/null;
if [[ $? == 0 ]]; then
mv $file.tmp $file && gofmt -w $file;
else
rm $file.tmp;
fi
else
rm $file.tmp;
fi
done
```
We want to distinguish different *kinds* of GroupCounts, so we're
making the GroupCounts parent object track its type so we can keep that
correct.
Adding this to protobuf, etc, then creates some weird behaviors
because sometimes we expect []GroupCount, and sometimes we expect
*GroupCounts. This implies changes to test cases. Also, the
changes to test cases imply that some test cases are probably now
wrong; for instance, they're expecting a "sum" column, equal to zero,
when no sum was requested.
We try to make the encoder handle a []*GroupCount gotten from another
node without panicing, and avoid breaking the semantics of the existing
messages, renumbering messages or components, etc.
Since a previous version, the `.Groups` member has been privatized,
and the `.Get()` convenience accessor has been renamed `.Groups()`
and is now used consistently in a way that should reduce the risk
of nil pointers causing crashes. Also, NewGroupCounts is used in
a couple more places.
