Add support for html in multipart/mixed
diff --git a/parsemail.go b/parsemail.go
index 42e0170..6a60192 100644
--- a/parsemail.go
+++ b/parsemail.go
@@ -249,6 +249,13 @@
 			}
 
 			textBody += strings.TrimSuffix(string(ppContent[:]), "\n")
+		} else if contentType == contentTypeTextHtml {
+			ppContent, err := ioutil.ReadAll(part)
+			if err != nil {
+				return textBody, htmlBody, attachments, embeddedFiles, err
+			}
+
+			htmlBody += strings.TrimSuffix(string(ppContent[:]), "\n")
 		} else if isAttachment(part) {
 			at, err := decodeAttachment(part)
 			if err != nil {