Minor tweaks (#154)

* Minor tweaks

Use at your own risk. Just thought I’d contribute at least a little bit

* Exit code 0

Exit code 0 is standard for notifying the system of a regular, non-error exit.

* No longer need unnecessary flag

* Fix `already_tagged` not defined

* <3 Zen of Python

* Silly me

core/misc.py

@@ -127,7 +127,7 @@ def filter_path(path):
 
 def grace_quit():
     print('\n\nExiting.')
-    sys.exit()
+    sys.exit(0)
 
 def get_sec(time_str):
    v = time_str.split(':', 3)