v5.8.1

• Convert library to a Go module
• Use an http.Transport with sensible defaults, based off the default transport in Go's standard library
• Add hooks to set max-idle-conns-per-host and idle-conn-timeout
• Fix integration test issues
• Add end-to-end Go context support. This is a breaking API change as virtually all public functions now accept a context as the first argument. This allows callers to cancel in-flight operations and propagate deadlines. A minimal mechanical change would be to pass in context.TODO() or context.Background().
• Add ignore_server_cert option
• Default endpoint to https:// if no scheme is provided
• "go fmt" all source code