Change "compress" to apply to a selection

I would find it useful if the “compress” command in DTPO’s SDEF would take a selection as its input. Now, it applies only to databases overall.

For extra credit, a new “uncompress” command would be welcome.

Uncompress <record> to <destination group>

Together, these would facilitate managing older records that I want to keep in the database, but would want to recoup space.