add arcomplete support

scripts/amodem

@@ -1,4 +1,6 @@
 #!/usr/bin/env python
+# PYTHON_ARGCOMPLETE_OK
+
 import sys
 if sys.version_info.major == 2:
     _stdin = sys.stdin
@@ -8,6 +10,8 @@ else:
     _stdout = sys.stdout.buffer
 
 import argparse
+import argcomplete
+
 import logging
 
 log = logging.getLogger('__name__')
@@ -104,6 +108,7 @@ def main():
         output_type=FileType('wb')
     )
 
+    argcomplete.autocomplete(p)
     args = p.parse_args()
     if args.verbose == 0:
         level, format = 'INFO', '%(message)s'