Remove .vimrc, MANIFEST.md, and the DESIGN directory
auto merge of #769 : tomaka/cargo/delete-design, r=alexcrichton
Extract custom build tests and prefix with "old_"
Deprecate old build system and add rust build script as target
Custom build commands are now being run
Build command output now being checked and written to filesystem
Flags from custom build script are now used
Jobs now send back their own description when they start
Add draft for passing metadata to dependencies
Deprecated a few more things
Address minor issues
Move custom-build-related code in its own module