Add support for unicode plugin

This commit adds support for the :UnicodeTable of https://github.com/chrisbra/unicode.vim

autoload/airline/extensions.vim

@@ -230,6 +230,10 @@ function! airline#extensions#load()
       call airline#extensions#nrrwrgn#init(s:ext)
   endif
 
+  if get(g:, 'airline#extensions#unicode#enabled', 1) && exists(':UnicodeTable') == 2
+      call airline#extensions#unicode#init(s:ext)
+  endif
+
   if (get(g:, 'airline#extensions#capslock#enabled', 1) && exists('*CapsLockStatusline'))
     call airline#extensions#capslock#init(s:ext)
   endif

autoload/airline/extensions/unicode.vim

@@ -0,0 +1,22 @@
+" MIT License. Copyright (c) 2013-2016 Bailey Ling.
+" vim: et ts=2 sts=2 sw=2
+
+if !get(g:, 'loaded_unicodePlugin', 0)
+  finish
+endif
+
+function! airline#extensions#unicode#apply(...)
+  if exists(":UnicodeTable") == 2 && bufname('') ==# 'UnicodeTable'
+    call airline#parts#define('unicode', {
+          \ 'text': '[UnicodeTable]',
+          \ 'accent': 'bold' })
+    let w:airline_section_a = airline#section#create(['unicode'])
+    let w:airline_section_b = ''
+    let w:airline_section_c = ''
+    let w:airline_section_y = ''
+  endif
+endfunction
+
+function! airline#extensions#unicode#init(ext)
+  call a:ext.add_statusline_func('airline#extensions#unicode#apply')
+endfunction