Lokaltog/powerline — pull request #912 by aegypius (2014-07-10 12:55:47+00:00)
Title: Fix buffer to string conversion in powerline-config

I've just fixed an issue when tmux background was not displayed using user config.

```shell
aegypius $> powerline-config tmux source
Traceback (most recent call last):
File "/home/aegypius/.local/bin/powerline-config", line 33, in
args.function(args)
File "/home/aegypius/.local/bin/powerline-config", line 15, in
'source': (lambda args: config.source_tmux_files()),
File "/home/aegypius/.local/lib64/python3.3/site-packages/powerline/bindings/config.py", line 107, in source_tmux_files
version = get_tmux_version()
File "/home/aegypius/.local/lib64/python3.3/site-packages/powerline/bindings/config.py", line 47, in get_tmux_version
_, version_string = version_string.split(' ')
TypeError: Type str doesn't support the buffer API
```