Merge 'save' and 'copy' command lists into one common list.

Merge 'save' and 'copy' command lists into one common list.

Previously we used separate lists for them; however the structure
of 'save' and 'copy' commands is almost identical, so its easy to
use one C struct for both types. Also, this simplifies analysis:
both types of commands are handled in a uniform way.

However, now we have to do list transformations like sorting and
deleleting duplicates in chunks.

This is a preliminary step to allow intermixing 'copy' and 'save'
commands.