Rename cargo to rustpkg and start over fresh
rustpkg: More preliminary work
rustpkg: Add package script parsing
rustpkg: Finish parsing package scripts and finish boilerplate
rustpkg: Finish declarative compiling and fetching via git or curl (no workcache or dependency resolution yet)
Add cmp::Ord implementation for semver::Version
rustpkg: Finish all commands and declarative logic
rustpkg: Add preliminary imperative API support
rustpkg: Add do command and get cmd listeners working correctly
rustpkg: More fixes
rustpkg: Clean up formatting issues
Correct Zack Corr's email in AUTHORS.txt
Move semver to std and finish rustpkg
rustpkg: Use pkg.rs instead of package.rs for consistency
rustpkg: Add info command for probing a pkg.rs and expose work_dir/src_dir in librustpkg
rustpkg: Fix do listeners and support custom test logic
rustpkg: Massage for landing.
auto merge of #4799 : graydon/rust/rustpkg, r=graydon

Taking over where #4610 left off. Much rebasing and tidying.