vim: unite: Use fuzzy search only for files and buffers
vim: unite: Remove limit for caching
vim: unite: use asynchronous variant of file_rec

The asynchronous variant of file_rec needs vimproc to be installed (and
compiled).
vim: replace deprecated powerline with airline

To display airline nicely we need a patched font. See

  https://github.com/bling/vim-airline#integrating-with-powerline-fonts
vim: install 'ft-csv' plugin

To avoid error messages at startup the 'syntax on' command has to be called
after ftplugin.
vim: add word to spellfile