Added rfxtrx rollershutter (#525)

* Added rfxtrx rollershutter

* Updated date and target release

source/_components/rollershutter.rfxtrx.markdown

@@ -0,0 +1,59 @@
+---
+layout: page
+title: "RFXtrx Rollershutter"
+description: "Instructions how to integrate RFXtrx roller shutters into Home Assistant."
+date: 2016-06-02 14:20
+sidebar: true
+comments: false
+sharing: true
+footer: true
+ha_category: Rollershutter
+ha_release: 0.21
+---
+
+The `rfxtrx` platform support Siemens/LightwaveRF roller shutters that communicate in the frequency range of 433.92 MHz.
+
+First you have to set up your [rfxtrx hub.](/components/rfxtrx/)
+The easiest way to find your roller shutters is to add this to your `configuration.yaml`:
+
+```yaml
+rollershutter:
+ platform: rfxtrx
+ automatic_add: True
+```
+
+Launch your homeassistant and go the website.
+Push your remote and your device should be added.
+
+Once added it will show an id (e.g `0b11000102ef9f210010f70`) and you can verify that it works from the frontend.
+Then you should update your configuration to:
+```yaml
+rollershutter:
+  platform: rfxtrx
+  devices:
+    0b11000102ef9f210010f70:
+      name: device_name
+```
+
+Example configuration:
+```yaml
+# Example configuration.yaml entry
+rollershutter:
+  platform: rfxtrx
+  automatic_add: False
+  signal_repetitions: 2
+  devices:
+    0b1100ce3213c7f210010f70:
+      name: Bedroom Shutter
+    0b11000a02ef2gf210010f50:
+      name: Bathroom Shutter
+    0b1111e003af16aa10000060:
+      name: Lounge Shutter
+```
+
+Configuration variables:
+
+- **devices** (*Required*): A list of devices with their name to use in the frontend.
+- **automatic_add** (*Optional*): To enable the automatic addition of new roller shutters.
+- **signal_repetitions** *Optional*: Because the rxftrx device sends its actions via radio and from most receivers it's impossible to know if the signal was received or not. Therefore you can configure the roller shutter to try to send each signal repeatedly.
+- **fire_event** *Optional*: Fires an event even if the state is the same as before. Can be used for automations.