rename fragments to parts.

autoload/airline/parts.vim

@@ -1,18 +1,18 @@
 " MIT License. Copyright (c) 2013 Bailey Ling.
 " vim: et ts=2 sts=2 sw=2
 
-function! airline#fragments#paste()
+function! airline#parts#paste()
   return g:airline_detect_paste && &paste ? '  '.g:airline_symbols.paste : ''
 endfunction
 
-function! airline#fragments#iminsert()
+function! airline#parts#iminsert()
   if g:airline_detect_iminsert && &iminsert && exists('b:keymap_name')
     return '  '.g:airline_left_alt_sep.' '.toupper(b:keymap_name)
   endif
   return ''
 endfunction
 
-function! airline#fragments#readonly()
+function! airline#parts#readonly()
   return &readonly ? g:airline_symbols.readonly : ''
 endfunction