Improve program documentation

youtube-dl

@@ -67,6 +67,7 @@ class FileDownloader(object):
 	_ies = []
 
 	def __init__(self, params):
+		"""Create a FileDownloader object with the given options."""
 		self._ies = []
 		self.set_params(params)
 	
@@ -305,7 +306,7 @@ class InfoExtractor(object):
 		return True
 
 	def initialize(self):
-		"""Initializes an instance (login, etc)."""
+		"""Initializes an instance (authentication, etc)."""
 		if not self._ready:
 			self._real_initialize()
 			self._ready = True
@@ -320,10 +321,12 @@ class InfoExtractor(object):
 		self._downloader = downloader
 	
 	def to_stdout(self, message):
+		"""Print message to stdout if downloader is not in quiet mode."""
 		if self._downloader is None or not self._downloader.get_params().get('quiet', False):
 			print message
 	
 	def to_stderr(self, message):
+		"""Print message to stderr."""
 		sys.stderr.write('%s\n' % message)
 
 	def _real_initialize(self):