This adds a shard-based import endpoint which takes bitmap data for
all field types and imports data for the whole shard transactionally.
It uses the BitmapRewriter interface to try to intelligently allow for
setting and clearing bits simultaneously without multiple writes which
is especially helpful when ingesting into int-like fields, but also
allows clear-and-then-set behavior for set fields.
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
```
