[update] gina's extensions in extensions dir

fix typo and add section_b

[add] extension gina

[add] unstaged extensions

[fix] typo

[Done] gina refactoring

[fix] document

[fix] gina's spell

[add] abort

autoload/airline/extensions/gina.vim

@@ -0,0 +1,20 @@
+scriptencoding utf-8
+if !get(g:, 'loaded_gina', 0)
+  finish
+endif
+
+function! airline#extensions#gina#apply(...) abort
+  if (&ft =~# 'gina' && &ft !~# 'blame') || &ft ==# 'diff'
+    call a:1.add_section('airline_a', ' gina ')
+    call a:1.add_section('airline_b', ' %{gina#component#repo#branch()} ')
+    call a:1.split()
+    call a:1.add_section('airline_y', ' staged %{gina#component#status#staged()} ')
+    call a:1.add_section('airline_z', ' unstaged %{gina#component#status#unstaged()} ')
+    return 1
+  endif
+endfunction
+
+function! airline#extensions#gina#init(ext) abort
+  let g:gina_force_overwrite_statusline = 0
+  call a:ext.add_statusline_func('airline#extensions#gina#apply')
+endfunction