fabtools added to dependencies
Now deb_handler methods are using fabtools in vim.install task

Methods replaced:
    apt_update() -> update_index()
    apt_install() -> is_installed(), install()
Now deb_handler methods are using fabtools in zsh.install task

Methods replaced:
    apt_update() -> update_index()
    apt_install() -> is_installed(), install()
Merge branch 'feature/using_fabtools'