Add iis ftp feature installation
user
```ruby
#
# Author:: Kevin Rivers (<kevin@kevinrivers.com>)
# Cookbook Name:: iis
# Recipe:: mod_ftp
#
# Copyright 2014, Kevin Rivers
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

include_recipe "iis"

if Opscode::IIS::Helper.older_than_windows2008r2?
  features = %w{Web-Ftp-Server Web-Ftp-Service Web-Ftp-Ext}
else
  features = %w{IIS-FTPServer IIS-FTPSvc IIS-FTPExtensibility}
end

features.each do |f|
  windows_feature f do
    action :install
  end
end
```
assistant