gb version 0.4.4

The 0.4 series focuses on improvements to project dependency management.

New features (since 0.4.3)

• depfile now supports tag=sometag in addition to version=semver. See #629
• gb now uses the go/build package for parsing source code. The previous importer introduced over the Dec 2015 break has been removed. No user visible change is expected.
• @gliptak has added a bunch of code hygiene tools to the CI process, and subsequently fixed a lot of style and hygiene issues. Thanks!

Bug fixes (since 0.4.3)

• gb-vendor no longer gets tripped up when a package refers to the copy of golang.org/x/net/http2/hpack vendored in the Go standard library after Go 1.6. Fixes #635
• gb-vendor now ignores invalid XML after tag when parsing vanity imports. Fixes #643. Thanks @seh
• gb now builds cgo packages correctly on distributions that default to -PIE mode. Fixes #607. Thanks @rdwilliamson
• gb-vendor now refuses to accept more than one argument when the -all flag is used. Thanks @nubunto
• gb-vendor restore now operates in parallel. Thanks @gsquire
• gb test now works with Go 1.8. Fixes #690. Thanks to @freeformz for the test case.