Fixed the initial population of the epoc32 tree with rnd bins to deal
with the fact that the zips are in a slightly different location. (cf
the changes made for Bug 350)
Simplified the way in which the setting of sf.spec.package.src.enable
is handled - no need to use it to change the zipping template, just use
it to control which parts of the template we invoke.
(binary:application/octet-stream)