WIP: FSM notified when a command is finished
WIP: FSM notified when a command is finished.

Refactorings in kernel to allow for cleaner reporting of command completions.
WIP: FSM notified when a command is finished.
WIP: FSM notified when a command is finished.

libtizonia unit tests now pass again
WIP: FSM notified when a command is finished.

Added 2 more unit tests to libtizonia:
- test_tizonia_command_cancellation_disabled_to_enabled_no_buffers;
- test_tizonia_command_cancellation_disabled_to_enabled_with_tunneled_supplied_buffers;