Execution time set reads

All of the statements up to now have used $Call which executes the Gdxxrw command at compilation time but some users may wish to load sets at execution time.  This is limited to subsets that are dynamic sets and cannot be used in domains.  To do this one simply uses the statements as above, but substitutes Execute in place of $Call as follows (Gdxxrwread.gms) where instead of

$Call "Gdxxrw gdxxrwss.xls set=i9 Rng=sheet1!b20:c21 cdim=1"

one uses

Execute "Gdxxrw gdxxrwss.xls set=i9 Rng=sheet1!b20:c21 cdim=1"