simplify serialrx by Cesco
fix bug in softserial with digitalIn usage (todo rewrite this properly)

git-svn-id: https://afrodevices.googlecode.com/svn/trunk/baseflight@425 7c89a4a9-59b9-e629-4cfe-3a2d53b20e61
calculate heading using gyro-only on boards without mag - idea by Cesco
added constants for gyro/acc/baro cal and fixed calibration to add /2
warning cleanup in drv_serial.c

git-svn-id: https://afrodevices.googlecode.com/svn/trunk/baseflight@426 7c89a4a9-59b9-e629-4cfe-3a2d53b20e61
reset heading to zero when calibrating gyro w/stick combo on hardware without mag

git-svn-id: https://afrodevices.googlecode.com/svn/trunk/baseflight@427 7c89a4a9-59b9-e629-4cfe-3a2d53b20e61
fixed a fuckup with yaw_rate that was caused by more 8bit leftover garbage
fixed althold vel/constrain typo thx Marcin
flight-tested this build on my shitcopter, CAREFUL flight testing may commence.

git-svn-id: https://afrodevices.googlecode.com/svn/trunk/baseflight@428 7c89a4a9-59b9-e629-4cfe-3a2d53b20e61
fixed buzzer on rev5 boards;
added experimental gyro-based headfree boxes

git-svn-id: https://afrodevices.googlecode.com/svn/trunk/baseflight@429 7c89a4a9-59b9-e629-4cfe-3a2d53b20e61
Merge remote-tracking branch 'multiwii/upstream'

Conflicts:
	src/drv_system.c
	src/main.c
fixing buzzer related compilation errors on OLIMEXINO target.
Softserial can now be enabled/disabled via the SOFTSERIAL feature switch in the command line.  Softserial baud rate can be set via softserial_baudrate setting. Added input & output inversion support, use softserial_inverted setting.