Create log_dir path directories recursively

This change will create the custom log folder and its parents, if needed, in the case of using absolute paths too.
Move buffer format conversion to its own file and import it.
Make blit_buffer accept memoryviews and objects that implement the buffer interface in additon to bytes. Use new conversion function.
Update urlrequest.py

Added '''and the response
to the request will be accessible as the parameter called "result" on the callback
function of the on_success event.'''.
Use proper memoryview for data bufferfmt.
Changed EffectWidget default background

...from (1, 1, 1, 1) to (0, 0, 0, 1) to match the
default Window clearcolor.
Fix missing 'string.lower()' after cleanup
Merge pull request #2192 from inclement/efw

Changed EffectWidget default background
doc: changed 'testdrive' to 'kivy android vm' in prep for vm docs
Merge branch 'master' of https://github.com/kivy/kivy
doc: added dedicated VM docs
Merge pull request #2203 from suriyan/master

Fix missing 'string.lower()' after cleanup
Add on_bring_to_front event to Scatter
Disable indent-tabs-mode in kivy-mode.el.
doc: fix some versionadded to versionchanged.

Signed-off-by: Mathieu Virbel <mat@kivy.org>
Merge branch 'master' of ssh://github.com/kivy/kivy

Conflicts:
	kivy/network/urlrequest.py
doc: added hints and tips for Kivy VM usage
doc: claried the widget background example
Merge pull request #2207 from richkinder/emacs_kivy_mode_tab_removal

Disable indent-tabs-mode in kivy-mode.el.
doc: changed example to use standard 4 space indentation