Fix `brew` completion, history substring search, and add `extract` function.
Squashed 'vim/bundle/neobundle.vim/' changes from a198d71..ab06551

ab06551 Merge pull request #259 from k-takata/topic/update-document-for-vimproc
fd346a8 update document for vimproc on Windows

git-subtree-dir: vim/bundle/neobundle.vim
git-subtree-split: ab065519eeae2c77a9483d42ff877291f833d5cf
Merge commit '0b9bf87ec614e5df281aec6a0b9c513423c05c1d'