title: git rebase doesn't show merge commits
body: <p>When I do <code>git rebase -i HEAD~4</code> I get something like this:</p>
  
  <pre><code>pick 7e2dd90 refactor some function
  pick dad8a9e fix another bug
  pick 4ba8c24 add another feature
  pick aca4ba3 do other stuff
  pick dd0b3e6 add feature
  pick 8dad92f fix bug
  pick 8571d0c stuff
  pick 25b328c whatever
  pick 1803bca demo commit
  pick 9723acc hello, world
  pick 3ff4212 blahblah
  pick c5c3bcf missed a file in merge
  </code></pre>
  
  <p>When I do <code>git log</code> I get this:</p>
  
  <pre><code>commit c5c3bcf0ac65d1423ddc2785b2f9ac3ecbd930d9
  Author: neubert
  Date:   Sat Mar 28 22:11:08 2015 -0500
  
      missed a file in merge
  
  commit 198bb3c61f62de47706fdfa3171bb79b4a0496a1
  Merge: cae37ae bb01002
  Author: neubert
  Date:   Sat Mar 28 21:54:51 2015 -0500
  
      Merge branch 'branchname' into anotherbranch
  
      Conflicts:
          path/to/filename.ext
  
  commit bb01002233f1eff5d42b6964e33830633f710ee1
  Merge: c8fe3c3 3ff4212
  Author: neubert
  Date:   Sat Mar 28 21:03:17 2015 -0500
  
      Merge remote-tracking branch 'athirdbranchname'
  
  commit 3ff4212b9291f2c863a742f5692ca7312b81decb
  Author: neubert
  Date:   Tue Mar 24 13:40:42 2015 +0800
  
      blahblah
  
  commit 9723acc8853c5fe7ea9bda4a9a711a3e07575c84
  Author: neubert
  Date:   Tue Mar 24 13:38:56 2015 +0800
  
      hello, world
  </code></pre>
  
  <p>My question is...  why isn't <code>git rebase</code> showing merge commits? Is that just not something it does? I'd like to squash the "missed file in merge" commit to the merge commit but if I can't see it with rebase I can't do that..</p>
  
  <p>Also, shouldn't <code>git rebase -i HEAD~4</code> give me four commits - not 12?</p>