examples/ostest:  Extend the pthread cancellation test to exercise pthread_cleanup_push() (and pthread_cleanup_pop() indirectly via pthread_cancel() and pthread_exit()

Remove BOARDIOC_CAN_INITIALIZE.  CAN initialization is now done in the board initialization logic just like every other device driver.

Import patch to fix:cJSON_PrintUnformatted() behaves unexpected if an empty array shall be printed to text. from Jerome Lang 2012-04-19

The examples/qencoder app was trying to init the encoder by a direct call into the board, cheating in a local header to declare the normally unavailable function prototype.

Fixed bug that didn't free ftpd ressources on end of session

Revert "apps/examples/ostest: Skip the task_restart() test on SMP systems.  This is not fully implemented."

This reverts commit 0ce49462.

Revert "apps/examples:  Remove the timer example.  It uses a non-portable IOCTL and must be purged."

This reverts commit dba181d0.