Implement tests for config.vim
Update readme
Join all lines in buftabs.vim and formatter.vim
Load settings just once
Move displaying responsibilities to a separate file
Implement an integrationt test
Move responsibility of adding active markers to main script
Replace all tabs with spaces
Simplify display.vim
Make sure display works with custom statusline
Remove Buftabs_enable()
Tidy up
Improve function g:BuftabsConfig
Let the formatter extract formatter pattern from config
Update copyright notices
Shorten lines
Improve tabs spacing
Improve overflow markers
Make display adjust truncating to current index