New commands for { install, upgrade, uninstall, list } packages directly from crates.io

[icorderi]

A cargo install foobar is far more convenient and clean than:

git clone foobar.git, 
cd foobar
cargo build --release
ln -s target/release/foobar /usr/local/bin/.

modulo error checks...

We will probably need the siblings too, cargo uninstall foobar, cargo upgrade foobar.

While we are at it:

• cargo view foobar for checking details on an installed package and,
• cargo list for the list of packages, versions installed
• cargo upgrade, latest and greatest for all the installed crates.

cargo package foobar would allow one to deploy without cargo on the target (originally posted in #557).

Where do we want this?

Do we want this features under cargo? or should be start building a crane and split compilation related features (cargo) from package management and deployment (crane).

[steveklabnik]

There's already a ticket open for this, and we even had a PR with a basic implementation, though it ended up not landing. So I'm closing as a duplicate.

[alexcrichton]

We're specifically tracking the story of cargo install and all related features in #37.