use code 160 for space to fix rendering problems.
Merge branch '256' into dev

Conflicts:
	autoload/airline/init.vim
fix broken test.
use __accent to better differentiate between a real group.
bring back readonly by default for section_c in overrides (#270).
do not render accents in inactive splits. resolves #270.
bufenter is sufficient to detect buffer list changes.
disable arrows by default for tabline.
Merge branch 'master' into dev