Add the ability for a callback to be run with interrupts disabled
Jeffrey Lee authored
Detail:
  c/callx, h/callx, s/veneer - Added new callx_add_callback_irqsoff function.
  This is identical to callx_add_callback, except the callback function will be entered with IRQs disabled.
  Using this function makes it safe to cancel callbacks from interrupts, as there's no longer the chance of a callback firing after it's been deleted.
Admin:
  Tested on rev A2 BB-xM.


Version 0.08. Tagged as 'callx-0_08'
9a2d21ca