Relocated led strip user code into separate file.

Added documentation.

Added LED_STRIP feature, can only be enabled under certain circumstances
depending on target due to pin/timer mappings - see documentation.

docs/LedStrip.md

@@ -0,0 +1,97 @@
+# Led Strip
+
+Cleanflight supports the use of addressable LED strips.  Addressable LED strips allow each LED in the strip to
+be programmed with a unique and independant color.  This is far more advanced than the normal RGB strips which
+require that all the LEDs in the strip show the same color.
+
+Addressable LED strips can be used to show information from the flight controller system, the current implementation
+supports the following:
+
+* Indicators showing pitch/roll stick positions.
+* Heading/Orientation lights.
+* Flight mode specific color schemes.
+* Low battery warning.
+
+In the future, if someone codes it, they could be used to show GPS navigation status, thrust levels, RSSI, etc.
+Lots of scope for ideas and improvements.
+
+Likewise, support for more than 10 LEDs is possible, it just requires additional development.  10 was chosen to
+start with due to current draw and RAM usage.
+
+## Supported hardware
+
+Only strips of 10 WS2812 LEDs are supported currently.  If the strip is longer than 10 leds it does not matter,
+but only the first 10 are used.
+
+WS2812 LEDs require an 800khz signal and precise timings and thus requires the use of a dedicated hardware timer.
+
+Note: The initial code may work with WS2801 + External LEDs since the protocol is the same, WS2811/WS2812B should also work but
+may require very simple timing adjustments to be made in the source.
+Not all WS2812 ICs use the same timings, some batches use different timings.  
+
+It could be possible to be able to specify the timings required via CLI if users request it.
+
+## Connections
+
+WS2812 LED strips generally require a single data line, 5V and GND.
+
+WS2812 LEDs on full brightness can consume quite a bit of current.  It is recommended to verify the current draw and ensure your
+supply can cope with the load.  On a multirotor that uses multiple BEC ESC's you can try use a different BEC to the one the FC
+uses.  e.g. ESC1/BEC1 -> FC, ESC2/BEC2 -> LED strip. 
+
+
+| Target                | Pin | Led Strip |
+| --------------------- | --- | --------- |
+| Naze/Olimexino        | RC5 | Data In   |
+| ChebuzzF3/F3Discovery | PB8 | Data In   |
+
+
+Since RC5 is also used for SoftSerial on the Naze/Olimexino it means that you cannot use softserial and led strips at the same time.
+Additionally, since RC5 is also used for Parallel PWM RC input on both the Naze, Chebuzz and STM32F3Discovery targets, led strips
+can not be used at the same time at Parallel PWM.
+
+## Positioning
+
+Cut the strip of 10 LED's in half,  the first half goes at the front of the quad, from front left to from right. Position
+the center LED in the middle.  When the strips are cut ensure you reconnect each output to each input with cable where the break is made.
+e.g. connect 5V out to 5V in, GND to GND and Data Out to Data In.
+
+The second half of the strip goes at the back of the aircraft, from back right to back left, again place the center LED in the middle.
+
+Orientation is when viewed with the front of the aircraft facing away from you and viewed from above.
+
+Example LED numbers and positions for a quad.
+
+```
+ 1  2        4  5
+   \           /
+    \    3    / 
+     \ FRONT /
+     /  BACK \
+    /    8    \
+   /           \
+10  9         7  6  
+```
+
+## Configuration
+
+Enable the `LED_STRIP` feature via the cli:
+
+```
+feature LED_STRIP
+```
+
+If you enable LED_STRIP feature and the feature is turned off again after a reboot then check your config does not conflict with other features, as above.
+
+## Troubleshooting
+
+On initial power up the first 10 LEDs on the strip will be set to WHITE.  This means you can attach a current meter to verify
+the current draw if your measurement equipment is fast enough.  This also means that you can make sure that each R,G and B LED
+in each LED module on the strip is also functioning.
+
+After a short delay the LEDs will show the unarmed color sequence and or low-battery warning sequence.
+
+If the LEDs flash intermittently or do not show the correct colors verify all connections and check the specifications of the
+LEDs you have against the supported timings (for now, you'll have to look in the source).
+
+Also check that the feature `LED_STRIP` was correctly enabled and that it does not conflict with other features, as above.