Fused read to compressed

This task is to while reading in a matrix, trying to compress it.

This would have to overwrite the read command and change it into a fused read-compress command.

(Easier) One approach is to construct bit maps of the individual columns as they are read from file directly. Then after these bitmaps are constructed decide to join columns together.

(Harder but probably better) Another is to use the first couple of blocks read to decide on a co coding scheme, and then directly put the read matrix into the compressed state.