Improve SBus code.  Fix SBus Failsafe detection, tested with FrSky X8R
and X4RSB.  Check for end-byte to improve robustness.

Less logic.  Better definition of frame structure eliminates the '-1's.
LedStrip failsafe warning now correctly checks that the feature is
enabled.
Update failsafe documentation.
Update README.md

I think we need a link to the Cleanflight releases in the Read Me.
Merge pull request #269 from Akfreak/patch-3

Update README.md
Support ALIENWIIF1 as an separate target
This will allow to build an HEX file independently to the NAZE target

An ALIENWIIF3 may also come in the future based on STM32F303. Both
likely will share the same default settings. This is why I don’t use
ALIENWII32 as target name yet.
Merge pull request #271 from MJ666/AlienWii32_target

Support ALIENWIIF1 as an separate target
wip Fix other targets
Merge branch 'master' of https://github.com/hydra/cleanflight

Conflicts:
	Makefile