Added multi-threading for tts functionality. Overal code improvements.

README.md

@@ -32,7 +32,7 @@ FileMAC [options] stdin format
 Replace `[options]` with the appropriate command-line options based on the functionality you want to execute.
 
 ## Available Options
-
+``*``
 - `1`:  --convert_doc         (doc* inter-conversion + tts)
 - `2`:  --convert_audio
 - `3`:  --convert_video