Merge branch '21-manual' into 23
Merge branch '21-scalars' into 23
Merge branch '22-more-scalars' into 23
use copy_3_strings in cross_colon
Merge branch '21-misc-cleanup' into 23
Merge branch '21-misc-cleanup' into 24
add checks on from, to, by being of length 1
Merge branch '23-seq-rep' into 24