Squashed 'bundle/vimshell-pure/' content from commit 03990fb

git-subtree-dir: bundle/vimshell-pure
git-subtree-split: 03990fb635844d9ae389eeb6af28a46a5b92cdf9
Merge commit '21780a5c093d60379cb2d7662f66d2ca21aeb0c3' as 'bundle/vimshell-pure'