cargo install for easy installation of tools

Cargo has grown a new install command. This is intended to be used for installingnew subcommands for Cargo, or tools for Rust developers. This doesn't replace the needto build real, native packages for end-users on the platforms you support.

For example, this guide is created with mdbook. Youcan install it on your system with

1. $ cargo install mdbook

And then use it with

1. $ mdbook --help

Cargo Extensions

As an example of extending Cargo, you can use the cargo-updatepackage. To install it:

1. $ cargo install cargo-update

This will allow you to use cargo install-update -a command, which checks everything you've cargo install'd andupdates it to the latest version.