Checks whether scroll-bar-mode is defined before calling it.
* The terminal version of Emacs 24.1.50.1 does not load
scroll-bar-mode and hence throws an error when loading
powerline. This patch only stops the error from appearing.
However, the modeline becomes totally green and unusable
in the terminal on Mac OS X. That needs fixing.
Checks whether scroll-bar-mode is defined before calling it.
Fixes a typo in the readme.
Patch to project approved.