LP#1274999: Adjust TT syntax to match project style

LP#1274999: Adjust TT syntax to match project style

Using a "$" sigil on a variable is confusing because that normally means
something special in TT, that the value of the variable, rather than the
variable name, should be used when accessing an array or hash by index or
key.

Instead, we can use the "last" vmethod provided for lists to directly
access the last element of the array, and then consult the size of that
list with "count".

Also removed is the sigil on the total_copies variable.

Signed-off-by: Mike Rylander <mrylander@gmail.com>