Fix help for --proxy

README.md

@@ -31,7 +31,7 @@ which means you can modify it, redistribute it or use it however you like.
                                is restricted to one domain
     --list-extractors          List all supported extractors and the URLs they
                                would handle
-    --proxy None               Use the specified HTTP/HTTPS proxy
+    --proxy URL                Use the specified HTTP/HTTPS proxy
 
 ## Video Selection:
     --playlist-start NUMBER    playlist video to start at (default is 1)

youtube_dl/__init__.py

@@ -146,7 +146,7 @@ def parseOpts(overrideArguments=None):
     general.add_option('--list-extractors',
             action='store_true', dest='list_extractors',
             help='List all supported extractors and the URLs they would handle', default=False)
-    general.add_option('--proxy', dest='proxy', default=None, help='Use the specified HTTP/HTTPS proxy')
+    general.add_option('--proxy', dest='proxy', default=None, help='Use the specified HTTP/HTTPS proxy', metavar='URL')
     general.add_option('--test', action='store_true', dest='test', default=False, help=optparse.SUPPRESS_HELP)
 
     selection.add_option('--playlist-start',