custom_build: build output goes in the directory for the req, not hard coded to Target

This broke crossbuilds that had Host deps that used custom build
scripts, typically resulting in a failure to link (due to bad
relocations or symbols) the final executable or library.

Probably should have rustc check when generating an rlib that all the
containing objects have the appropriate arch.
Add support for a custom arguments list when running main.
auto merge of #1042 : cgaebel/cargo/execute-main-with-custom-args, r=alexcrichton
print non-fatal errors to stdout instead of stderr

e.g. docopt treat version as non-fatal error

Fixes #1033
fix fatal condition
add test: cargo --version
auto merge of #1051 : liigo/cargo/print-version-to-stdout, r=alexcrichton

e.g. docopt treat version (and help) as non-fatal error

Fixes #1033
Warn if none of documentation, homepage or repository are provided

It's really hard to find out any information about a project if it
doesn't have any of these.

As a bonus I added a shebang to .travis.install.deps.sh so the README
instructions actually work.

Closes #998
auto merge of #1053 : sfackler/cargo/master, r=alexcrichton

It's really hard to find out any information about a project if it
doesn't have any of these.

As a bonus I added a shebang to .travis.install.deps.sh so the README
instructions actually work.

Closes #998
Fix mac nightly builds

Older versions of curl apparently don't peel off the query parameters when
looking up filenames, so make two copies of the search results file in hope that
curl will find one of them!
auto merge of #1057 : alexcrichton/cargo/fix-nightly, r=brson

Older versions of curl apparently don't peel off the query parameters when
looking up filenames, so make two copies of the search results file in hope that
curl will find one of them!
Merge branch 'fix-custom-build-cross' of https://github.com/jmesmon/cargo into pr-1012
Add a test for PR #1012
auto merge of #1060 : alexcrichton/cargo/pr-1012, r=alexcrichton
Update git2 and cargo snapshots

Should fix #1032 and #1029