support controlling whether bufferline variables get overwritten. resolves #195.

autoload/airline/extensions/bufferline.vim

@@ -1,7 +1,10 @@
 " MIT License. Copyright (c) 2013 Bailey Ling.
 " vim: et ts=2 sts=2 sw=2
 
+let s:overwrite = get(g:, 'airline#extensions#bufferline#overwrite_variables', 1)
+
 function! airline#extensions#bufferline#init(ext)
+  if s:overwrite
     highlight bufferline_selected gui=bold cterm=bold term=bold
     highlight link bufferline_selected_inactive airline_c_inactive
     let g:bufferline_inactive_highlight = 'airline_c'
@@ -9,6 +12,7 @@ function! airline#extensions#bufferline#init(ext)
     let g:bufferline_active_buffer_left = ''
     let g:bufferline_active_buffer_right = ''
     let g:bufferline_separator = ' '
+  endif
 
   let g:airline_parts.file = '%{bufferline#refresh_status()}'.bufferline#get_status_string()
 endfunction

doc/airline.txt

@@ -200,6 +200,15 @@ configuration values that you can use.
       \ 'y': 88,
       \ 'z': 45,
       \ })
+<
+                                                        *airline-bufferline*
+vim-bufferline <https://github.com/bling/vim-bufferline>
+
+* enable/disable bufferline integration >
+  let g:airline#extensions#bufferline#enabled = 1
+<
+* determine whether bufferline will overwrite customization variables >
+  let g:airline#extensions#bufferline#overwrite_variables = 1
 <
                                                             *airline-branch*
 fugitive.vim <https://github.com/tpope/vim-fugitive>