tests: Fixed typo in assertion message.
OpCompressedCache: Ensure that chunkshape is always smaller than the blockshape, even for edge blocks (which are smaller than the other blocks).
Added OpCompressedUserLabelArray as a drop-in replacement for OpBlockedSparseLabelArray (except for some outputs) and test (based on a modified version of the OpBlockedSparseLabelArray test)
OpFeatureMatrixCache: If there are no labels and therefore no features, return a 0-length matrix with the correct number of columns.
Merge branch 'compressed-user-labels'
OpDenseLabelArray: Allow MetaInput to have multiple channels, and force output shape to have 1 channel.