adding incsearch
Squashed 'vim/bundle/incsearch/' content from commit 8c422b5

git-subtree-dir: vim/bundle/incsearch
git-subtree-split: 8c422b58afefdc4331193bec307c9dd36b294074
Merge commit 'fc537b60740087129072b04e65ed7380e0327e29' as 'vim/bundle/incsearch'