Switch to new vendor directory layout

Fixes #113

Signed-off-by: Marcos Lilljedahl <marcosnils@gmail.com>

vendor/github.com/opencontainers/runc/libcontainer/stacktrace/frame.go

@@ -0,0 +1,38 @@
+package stacktrace
+
+import (
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+// NewFrame returns a new stack frame for the provided information
+func NewFrame(pc uintptr, file string, line int) Frame {
+	fn := runtime.FuncForPC(pc)
+	if fn == nil {
+		return Frame{}
+	}
+	pack, name := parseFunctionName(fn.Name())
+	return Frame{
+		Line:     line,
+		File:     filepath.Base(file),
+		Package:  pack,
+		Function: name,
+	}
+}
+
+func parseFunctionName(name string) (string, string) {
+	i := strings.LastIndex(name, ".")
+	if i == -1 {
+		return "", name
+	}
+	return name[:i], name[i+1:]
+}
+
+// Frame contains all the information for a stack frame within a go program
+type Frame struct {
+	File     string
+	Function string
+	Package  string
+	Line     int
+}