Create hg repo with --hg flag on cargo new
Tweak the install script for windows nightlies
auto merge of #537 : markberger/cargo/510-hg-flag, r=alexcrichton

Allows the client to initialize a mercurial repo when creating a new cargo project with `cargo new --hg`. This would close #510.

This is my first time writing code in rust outside of a toy program so please feel free to tear it apart or suggest an alternative solution.
Rewrite git tests to not rely on the CLI

The CLI has started to have differences on windows than on other systems, and
instead of coding against multiple CLI versions, instead just rewrite everything
to use libgit2.
auto merge of #574 : rust-lang/cargo/fix-win64, r=brson

These commits fix all tests and installation utilities on win64. I've confirmed that these are a green build on the bots.
Run tests with the --target flag
Pass profile env vars to build commands

Closes #553
auto merge of #558 : alexcrichton/cargo/issue-553, r=brson
Add a manpage

Closes #578
auto merge of #581 : alexcrichton/cargo/manpage, r=brson

Closes #578
Implement a `cargo fetch` command

This command is used to download all dependencies of a package ahead of time to
ensure that no more network communication will be necessary as part of a build.

cc #358