add profiler. optimize separator highlighting.

autoload/airline/debug.vim

@@ -0,0 +1,15 @@
+" MIT License. Copyright (c) 2013 Bailey Ling.
+" vim: et ts=2 sts=2 sw=2
+
+function! airline#debug#profile()
+  profile start airline-profile.log
+  profile func *
+  profile file *
+  split
+  for i in range(1, 50)
+    wincmd w
+    redrawstatus
+  endfor
+  profile pause
+  noautocmd qall!
+endfunction