add support for Velbus platform (#2830)

* add support for Velbus platform

* Update light.velbus.markdown

* update and extend documentation to be in line with updated pull request for code

* rename fan example to 'Fan 1'

source/_components/fan.velbus.markdown

@@ -0,0 +1,41 @@
+---
+layout: page
+title: "Velbus Fans"
+description: "Access and control your Velbus fans."
+date: 2017-06-17 16.58
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: velbus.png
+ha_category: Fan
+ha_iot_class: "Local Push"
+ha_release: 0.49
+---
+
+The `velbus` fan allows you to control [Velbus](http://www.velbus.eu) connected fans.
+
+To use your Velbus fans in your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+
+fan:
+  - platform: velbus
+    devices:
+       - name: Fan 1
+         module: 0xda
+         channel_low: 4
+         channel_medium: 3
+         channel_high: 2
+```
+
+Configuration variables:
+- **devices** array (*Required*): The array contains the fans to configure
+  - **name** (*Required*): Name of the fan.
+  - **module** (*Required*): The hexadecimal module address
+  - **channel_low** (*Required*): The channel number in the module for low-speed.
+  - **channel_medium** (*Required*): The channel number in the module for medium-speed.
+  - **channel_high** (*Required*): The channel number in the module for high-speed.
+
+For hub configuration, see [the Velbus component](/components/velbus/).