refactor the rest of the themes to use refresh. resolves #288.

autoload/airline/themes/base16.vim

@@ -1,4 +1,4 @@
-function! s:load_constant()
+if get(g:, 'airline#themes#base16#constant', 0)
   let g:airline#themes#base16#palette = {}
 
   " Color palette
@@ -60,9 +60,8 @@ function! s:load_constant()
   let g:airline#themes#base16#palette.inactive_modified = {
         \ 'airline_c': [s:gui_orange, '', s:cterm_orange, '', ''],
         \ }
-endfunction
-
-function! s:load_dynamic()
+else
+  function! airline#themes#base16#refresh()
     let g:airline#themes#base16#palette = {}
 
     let g:airline#themes#base16#palette.accents = {
@@ -102,15 +101,7 @@ function! s:load_dynamic()
     let g:airline#themes#base16#palette.inactive_modified = {
           \ 'airline_c': [ group[0], '', group[2], '', '' ]
           \ }
-endfunction
-
-if get(g:, 'airline#themes#base16#constant', 0)
-  call s:load_constant()
-else
-  call s:load_dynamic()
-  augroup airline_base16
-    autocmd!
-    autocmd ColorScheme * call <sid>load_dynamic() | call airline#load_theme()
-  augroup END
+  endfunction
+  call airline#themes#base16#refresh()
 endif
 

autoload/airline/themes/jellybeans.vim

@@ -1,6 +1,7 @@
 let g:airline#themes#jellybeans#palette = {}
 
-function! s:generate()
+" The name of the function must be 'refresh'.
+function! airline#themes#jellybeans#refresh()
   " This theme is an example of how to use helper functions to extract highlight
   " values from the corresponding colorscheme. It was written in a hurry, so it
   " is very minimalistic. If you are a jellybeans user and want to make updates,
@@ -47,8 +48,5 @@ function! s:generate()
   let g:airline#themes#jellybeans#palette.inactive_modified = g:airline#themes#jellybeans#palette.normal_modified
 endfunction
 
-call s:generate()
-augroup airline_jellybeans
-  autocmd!
-  autocmd ColorScheme * call <sid>generate()
-augroup END
+call airline#themes#jellybeans#refresh()
+

autoload/airline/themes/monochrome.vim

@@ -1,6 +1,6 @@
 let g:airline#themes#monochrome#palette = {}
 
-function! s:load()
+function! airline#themes#monochrome#refresh()
   let s:SL = airline#themes#get_highlight('StatusLine')
   let g:airline#themes#monochrome#palette.normal = airline#themes#generate_color_map(s:SL, s:SL, s:SL)
   let g:airline#themes#monochrome#palette.insert = g:airline#themes#monochrome#palette.normal
@@ -11,8 +11,5 @@ function! s:load()
   let g:airline#themes#monochrome#palette.inactive = airline#themes#generate_color_map(s:SLNC, s:SLNC, s:SLNC)
 endfunction
 
-call s:load()
-augroup airline_monochrome
-  autocmd!
-  autocmd ColorScheme * call <sid>load()
-augroup END
+call airline#themes#monochrome#refresh()
+

autoload/airline/themes/tomorrow.vim

@@ -1,6 +1,6 @@
 let g:airline#themes#tomorrow#palette = {}
 
-function! s:generate()
+function! airline#themes#tomorrow#refresh()
   let g:airline#themes#tomorrow#palette.accents = {
         \ 'red': airline#themes#get_highlight('Constant'),
         \ }
@@ -40,8 +40,5 @@ function! s:generate()
         \ }
 endfunction
 
-call s:generate()
-augroup airline_tomorrow
-  autocmd!
-  autocmd ColorScheme * call <sid>generate() | call airline#load_theme()
-augroup END
+call airline#themes#tomorrow#refresh()
+

autoload/airline/themes/zenburn.vim

@@ -1,6 +1,6 @@
 let g:airline#themes#zenburn#palette = {}
 
-function! s:generate()
+function! airline#themes#zenburn#refresh()
   let g:airline#themes#zenburn#palette.accents = {
         \ 'red': airline#themes#get_highlight('Constant'),
         \ }
@@ -40,9 +40,5 @@ function! s:generate()
         \ }
 endfunction
 
-call s:generate()
-augroup airline_zenburn
-  autocmd!
-  autocmd ColorScheme * call <sid>generate()
-augroup END
+call airline#themes#zenburn#refresh()