fix unicode typenames (illegal in py2)
fix unicode event names
fix stacklayout size_hint calculations to include spacing if necessary
better algorithm.
uix:Image introduce `anim_loop` property
Update image.py
shadereditor: allow to use another image in command line
core/audio: accept m4a as input format. could be added for android as well.
gstplayer: fix invalid size passed when we have a row stride (width * 3 not a multiple of 4). Closes  #2722
setup.py: don't activate automatically SDL2 until we have a mechanism that can load safely SDL2 libraries without anything related to SDL1.
fix erroneous doc
assert that event callbacks are actually callable
animation: fix crash when widget is gone. Closes #2458, #2561, #2676
Merge pull request #2718 from kivy/image_loop

uix:Image introduce `anim_loop` property
Merge pull request #2653 from kivy/fix_stacklayout_size_hint

Fix stacklayout size hint
widgets: add new ScatterPlaneLayout, based on #2682 but on a ScatterLayout as a base
Merge branch 'master' of ssh://github.com/kivy/kivy
Merge pull request #2724 from kived/bind-callable

assert that event callbacks are actually callable
Merge pull request #2639 from kived/factory-unicode-typename

fix unicode and Builder in Python 2
libtess2: fix unused variable warning when NDEBUG is activated