Tools: add unified device tree overlay to load all requisites

no more loading multiple capes to enable pru, spi, pwm etc. Steps to load the cape during boot also added.
Tools: Remove unrequired pru0 pin setups from BB-PXF-01-00A0 overlay
Merge branch 'master' of github.com:BeaglePilot/ardupilot into RCInput-wip