Update the character used in powerline

The code points have been updated in 53fbfe1, see
- https://github.com/Lokaltog/powerline/commit/53fbfe15fead8cc7598bcb4ee9714a221ab7e446
- https://github.com/Lokaltog/powerline/issues/4
Merge pull request #1872 from gdetrez/new-powerline-range

Update the character used from powerline