scripts: Simplified dbgtag.py, tweaked -x/--hex decoding

This drops the option to read tags from a disk file. I don't think I've
ever used this, and it requires quite a bit of circuitry to implement.

Also dropped -s/--string, because most tags can't be represented as
strings?

And tweaked -x/--hex flags to correctly parse spaces in arguments, so
now these are equivalent:

- ./scripts/dbgtag.py -x 00 03 00 08
- ./scripts/dbgtag.py -x "00 03 00 08"

scripts/parity.py

@@ -33,9 +33,10 @@ def parity(x):
 def main(paths, **args):
     # interpret as sequence of hex bytes
     if args.get('hex'):
+        bytes_ = [b for path in paths for b in path.split()]
         print('%01x' % parity(ft.reduce(
                 op.xor,
-                bytes(int(path, 16) for path in paths),
+                bytes(int(b, 16) for b in bytes_),
                 0)))
 
     # interpret as strings