Output name of the program for --version

'The GNU standard --version option should direct the program to print information about its name, version'
So added a name of program to version displaye along with shotr option \`-V'.

youtube_dl/options.py

@@ -118,7 +118,7 @@ def parseOpts(overrideArguments=None):
     fmt.format_option_strings = _format_option_string
 
     kw = {
-        'version': __version__,
+        'version': 'youtube-dl '+__version__,
         'formatter': fmt,
         'usage': '%prog [OPTIONS] URL [URL...]',
         'conflict_handler': 'resolve',
@@ -132,7 +132,7 @@ def parseOpts(overrideArguments=None):
         action='help',
         help='Print this help text and exit')
     general.add_option(
-        '--version',
+        '-V', '--version',
         action='version',
         help='Print program version and exit')
     general.add_option(