before replacing them (using pkgname to make this hopefully unique).
Delete also moves them back, if they exist, resulting in a package
which can be "backed out" with reasonable safety.
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
Made pkg_add -n less bitchy.
Made -p in pkg_add override "default" package location in pkg_create.
Added concept of "slave" and "master" modes, allowing many different things
to be done to packing lists on the fly. This is really something for
front-end drivers to use, but also something for the more expert user.
rename()'ing files before trying to copy them, thus saving
considerable time when targets and staging area are on same filesystem.
