merge: make debug output easier to read
I always found it hard to figure out what the debug code meant without
the separators.
#!/usr/bin/env python
# Filter output by the progress extension to make it readable in tests
import sys, re
for line in sys.stdin:
line = re.sub(r'\r+[^\n]', lambda m: '\n' + m.group()[-1:], line)
sys.stdout.write(line)
print