extensions: setup.py: add kivy.ext to packages. ext/__init__: don't crash if an extension path doesn't exist and cannot be created (Question: should we by default create the extensions/ folder in the kivy base dir...)

kivy/ext/__init__.py

@@ -203,7 +203,10 @@ def unzip_extensions():
 
     for epath in EXTENSION_PATHS:
         if not isdir(epath):
+            try:
                 mkdir(epath)
+            except OSError:
+                continue
             files = []
         else:
             files = listdir(epath)

setup.py

@@ -212,6 +212,7 @@ setup(
         'kivy.core.text',
         'kivy.core.video',
         'kivy.core.window',
+        'kivy.ext',
         'kivy.graphics',
         'kivy.input',
         'kivy.input.postproc',