1. delete exceptions.py

2. minor improvement

twitter_dl/exceptions.py

@@ -1,14 +0,0 @@
-class Error(Exception):
-    '''Base-class for all exceptions raised by this module.'''
-
-
-class ConfidentialsNotSuppliedError(Error):
-    '''An API key and an API sectret must be supplied.'''
-
-
-class BearerTokenNotFetchedError(Error):
-    '''Couldn't fetch the bearer token.'''
-
-
-class InvalidDownloadPathError(Error):
-    '''Download path must be a directory.'''