fix pep8 in kivy/__init__.py
pep8 fixes in kivy/animations.py
fix pep8 in kivy/app.py
fix pep8 in kivy/atlas.py
pep8 fixes in kivy/base.py
pep8 fixes in kivy/cache.py
pep8 fixes in kivy/clock.py
pep8 fixes in kivy/config.py
pep8 fixes in kivy/context.py
pep8 fixes for kivy/event.py
Merge pull request #1731 from kivy/pep8_fixes

Pep8 fixes