New SMTP library and refactoring of mailer code

vendor/gopkg.in/alexcesaro/quotedprintable.v3/pool_go12.go

@@ -0,0 +1,24 @@
+// +build !go1.3
+
+package quotedprintable
+
+import "bytes"
+
+var ch = make(chan *bytes.Buffer, 32)
+
+func getBuffer() *bytes.Buffer {
+	select {
+	case buf := <-ch:
+		return buf
+	default:
+	}
+	return new(bytes.Buffer)
+}
+
+func putBuffer(buf *bytes.Buffer) {
+	buf.Reset()
+	select {
+	case ch <- buf:
+	default:
+	}
+}