fix(build): don't require pillow for install

Author: accraze

setup.py

@@ -60,9 +60,7 @@ def read(*names, **kwargs):
     ],
     install_requires=[
         'click',
-        'awesome-slugify',
-        'Pillow',
-        'mock'
+        'awesome-slugify'
     ],
     extras_require={
         # eg:

src/livingdocs/maker.py

@@ -1,6 +1,5 @@
 from .hugo_doc import HugoDoc
 
-from PIL import Image
 from slugify import UniqueSlugify
 import os
 
@@ -70,6 +69,7 @@ def end_step(self, context, step):
 
         # get the screenshot
         try:
+            from PIL import Image
             context.browser.driver.get_screenshot_as_file(
                 '%s/%s/%s' % (self.output_dir, self.doc.path, shot_name))
         except: