Provide partial RTOS API for bare metal builds - things that
can be done in a single threaded environment.

Allows more code to work in both RTOS and bare metal builds without
change, and in particular gives easy access to the ability to
efficiently wait for something occurring in interrupt.

Available in bare-metal:
* ThisThread
* osThreadFlagsSet to set flags on main thread (can be set from IRQ)
* EventFlags (can be set from IRQ)
* Semaphores (can be released from IRQ)
* Mutex (dummy implementation)

Not useful:
* ConditionVariable (could only be signalled from 2nd thread)
* RtosTimer (calls in a second thread context)
* Thread

Unimplemented:
* Mail, Queue, MemoryPool

Possible future work:
* ConditionVariableCS to act as IRQ signalled ConditionVariable

Adjust some non-C++11-compatible code that failed as a result.

-Added the unit test case for testing Hw watchdog
    -Added the supported stubs files

enable_test() seems to include CTest framework in the CMakeLists.txt but
that would result in inconsistencies and CTest framework will not be
able to find DartConfiguration file or MemCheck tool.

Including CTest framework explicitely in the CMakeLists.txt seems to
solve the issue.

Add ip4tos() and stoip4() into unittests.
NOTE: Probably should have been stubbed but this way we can also
test these helper functions.