* Update Powerline for ipython >=7
The method used for `since_5` does not work, but `since_7` does, however it is not documented.
I personally haven't found `c = get_config()` to be useful once you have generated the default `~/.ipython/profile_default/ipython_config.py` file.
Since `c.TerminalInteractiveShell.simple_prompt` is set to `False` by default, it's not worth mentioning it. There's many other things that **can** break if you change the default config options too. Additionally, `simple_prompt=True` doesn't fatally break anything, just make things less pretty. So it'd be better to not have that, but mention if things don't look pretty to make sure they didn't change that default.
* Making it work on latest version
* spacing
Users may be confused when installing powerline as it does not appear by
default in single-window mode. This change alerts users that they should
not expect to see the status line and points them to the help documents
for laststatus so that they can activate it in all cases if they want.
Most of the files are empty and need to be copied or rewritten from the
old docs. Font patching docs have been removed entirely and will be
moved to the powerline-fontpatcher repo.
Ref #769
