Revamped drv_mpu to autodetect and support all currently used Invensense devices

New airplane tab in configurator for fixed wing settings.

Support for BMP280 barometer (afromini amaze), reversed (but now correct) servo midrc handling. Check servo travel direction after upgrading and reverse if necessary.
Fix throttle limiter on fixed wing.

Improved support for custom servo mixer, requires configurator update as well.
Support for SyncPWM on simonk firmware.
Brushed motors PWM frequency is now in configurator GUI.