[ramon]: fixed bug where downsampling a voxel had a negative exponent
[ramon]: fixed bug where downsampling a voxel had a negative exponent

openconnectome/open-connectome,openconnectome/open-connectome,openconnectome/open-connectome,openconnectome/open-connectome,openconnectome/open-connectome,openconnectome/open-connectome,neurodata/ndstore,neurodata/ndstore,neurodata/ndstore,neurodata/ndstore