Summary

This PR extends ghq to support Subversion (SVN) and Git-SVN repositories. It introduces automatic VCS backend detection and configuration, allowing `ghq clone` to perform `svn checkout` and `git svn clone`, and `ghq update` to perform `svn update` and `git svn rebase`.

Changes

Impact Areas

Files Changed

• cmd/ghq/main.go
• protocol/protocol.go
• protocol/git.go
• protocol/svn.go
• protocol/git_svn.go
• test/helper/helper.go