title: UltiSnips and YouCompleteMe
body: <p>I have bundles ultisnips and youcompleteme installed on my macvim.
  The problem is that ultisnips doesn't work because tab is bound by ycm.
  I tried putting <code>let g:UltiSnipsExpandTrigger = "&lt;s-tab&gt;"</code> so that I can trigger the snippet completion with shift-tab, but it doesn't work for some unknown reason. I could use caps as the trigger, but so far I've found no way to do that.</p>
  
  <p>Do any of you use those two add-ons together?
  What can I do to make shift-tab work?
  Can you recommend another key to trigger snippets?</p>