Fix tests

IPython/nbconvert/writers/__init__.py

@@ -1,3 +1,3 b''
 from .files import FilesWriter
 from .stdout import StdoutWriter
-from .pdf import PDFWriter
+from .base import WriterBase

IPython/nbconvert/writers/debug.py

@@ -1,4 +1,3 b''
-#!/usr/bin/env python
 """
 Contains debug writer.
 """

IPython/nbconvert/writers/files.py

@@ -1,4 +1,3 b''
-#!/usr/bin/env python
 """
 Contains writer for writing nbconvert output to filesystem.
 """

IPython/nbconvert/writers/stdout.py

@@ -1,4 +1,3 b''
-#!/usr/bin/env python
 """
 Contains Stdout writer
 """