sched/: Convert legitimate uses of task_create() to nxtask_create(). Review handling of returned values from all uses of kthread_create() (as well as nxtask_create()).
graphics/: Review return values for all calls to kthread_start() because it no longer returns an errno.
drivers/: threads started by drivers should be kernel threads, not user tasks. Review return values for all calls to kthread_start() because it no longer returns an errno.
configs/: threads started by board bringup logic should be kernel threads, not user tasksi (part 2 of 2).
sched/task: Add nxtask_create(). Kthread_create() and nxtask_create() are internal OS functions and should not modify the errno variable. configs/: threads started by board bringup logic should be kernel threads, not user tasks.
Provide a user defined callback context for irq's, such that when
registering a callback users can provide a pointer that will get
passed back when the isr is called.
