Rewrite using a modular command assembler; new features include:

- "extract audio" workflow: video -> wav|ogg
 - majorly cleaned up code
 - both --audio and --video codec options now accept "copy" and "drop"
 - dropped ogv support

aux.py

@@ -1,6 +1,8 @@
 #! /bin/env python3
 # encoding: utf-8
 
+import os
+import pathlib
 import queue
 import subprocess
 import sys
@@ -147,3 +149,17 @@ def parse_fps(raw):
 		return float(num) / float(den)
 	
 	return float(raw)
+
+# --------------------------------------------------
+
+def to_Path(raw_path):
+	'''
+	Returns pathlib.Path pointing to raw_path, handling "~/" correctly.
+	
+	To be removed after python:3.5 move.
+	'''
+	
+	if raw_path.startswith('~'):
+		raw_path = os.path.expanduser(raw_path)
+	
+	return pathlib.Path(raw_path)