Create durant.vim

add airline scheme
Update durant.vim

remove comments
Improve tabline + buffer_min_count behaviour

Use BufEnter and BufUnload in place of CursorMoved.

Fixes #479
fix regression with serene theme, #599
Merge pull request #547 from kdurant/master

Create durant.vim
Merge pull request #643 from maek/master

Improve tabline + buffer_min_count behaviour