actualise dead link to Ublox M8 V15-17 Receiver Description Protocol Spec ( new R08 from 4 December 2014)

Multiplatform 1741 and 1801

This reverts commit c0f1d841.

multiplatform port of #1741 and #1801: port attitude setpoint generation in manual to mc_pos_control_multiplatform

port #1752 to multiplatform

port #1703 to multiplatform

Quaternion method tests

this is the default mode ArduPilot uses, and by setting it in the init
script we avoid any pin activity on the two GPIO pins during boot

this allows for input of PWM signals on the FMUv2 aux5 pins

PWM command: Fix min/max/disarmed/failsafe commands to also read the current settings first before modifying them.

smart batteries report a negative current when being discharged