Merge remote-tracking branch 'MavLink/master'

* MavLink/master:
  android remote duplicate screen support
  Double-check link status after signal comes through
  Warning on running out of mavlink channels
  Mini-protocols must only communicate over single link
  Add priorityLink and sendMessageOnLink
  Keep track of USB direct connection links
  Remove change which is in another pull
  Mini-protocols must only communicate over single link
  Add priorityLink and sendMessageOnLink
  Keep track of USB direct connection links