Add go-charset and chardet to vendor

vendor/github.com/paulrosania/go-charset/charset/file.go

@@ -0,0 +1,40 @@
+package charset
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+var files = make(map[string]func() (io.ReadCloser, error))
+
+// RegisterDataFile registers the existence of a given data
+// file with the given name that may be used by a character-set converter.
+// It is intended to be used by packages that wish to embed
+// data in the executable binary, and should not be
+// used normally.
+func RegisterDataFile(name string, open func() (io.ReadCloser, error)) {
+	files[name] = open
+}
+
+// CharsetDir gives the location of the default data file directory.
+// This directory will be used for files with names that have not
+// been registered with RegisterDataFile.
+var CharsetDir = "/usr/local/lib/go-charset/datafiles"
+
+func readFile(name string) (data []byte, err error) {
+	var r io.ReadCloser
+	if open := files[name]; open != nil {
+		r, err = open()
+		if err != nil {
+			return
+		}
+	} else {
+		r, err = os.Open(filepath.Join(CharsetDir, name))
+		if err != nil {
+			return
+		}
+	}
+	return ioutil.ReadAll(r)
+}