Revert "Fix sigbits decoding to handle the 0-commonbits case"
Revert "Fix sigbits decoding to handle the 0-commonbits case"

This reverts commit ca64830e53cdae288e80fb8a127c2a86cf141c2f.

It broke other cases, better to rethink (#69)

BillTian/pointcloud,BillTian/pointcloud,BillTian/pointcloud