cargo-vendor - Cargo subcommand to vendor crates.io dependencies

This is a Cargo subcommand which vendors all crates.io dependencies into a
local directory using Cargo's support for source replacement.

cargo-vendor is helpful for packaging applications which use cargo (rust).

By default, the slackbuild requires all crate dependencies to be downloaded
individually. Optionally, if you already have cargo-vendor installed, you can
create a "vendored" tarball which contains all the crate dependencies exploded
into a single directory and then compressed together as a tarball.

The script cargo-vendor-mkvendortarball.sh will generate this for you. The slackbuild
will automatically use this tarball if found in the current directory.
