RTOS API for bare metal ...

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

Change EventFlag timeout paramter ...

Matches rest of RTOS class timeout parameters by using the unit name. Remove ambigious statement in reference to 0 ms being no-timeout as a timeout of 0 causes the function to not block and return immediately (osWaitForever is used as no timeout as it will wait forever)

Make Thread methods const

Add ThisThread

Style clean-up of Thread-related files

Added description of tz_module and MBED_TZ_DEFAULT_ACCESS

Overloaded ctor for new parameter tz_module

Trust zone module identifier added to thread class ...

Non-Secure threads can access secure calls only when tz_module attribute is set
as 1(OS_SECURE_CALLABLE_THREAD), while thread creation.
Hence adding tz_module as an argument to ctor.

Add Thread::wait_until ...

API is somewhat loose to cope with potential shift in the underlying
RTOS APIs.

Copy edit Thread.h ...

Copy edit file for active voice.

Add notes about ISR safety to RTOS doxygen

Doxygen comment updates and fixes

Doxygen comment fix for Thread class

Remove use of internal RTX types ...

Make calls to cmsis-os to get thread state, stack size, and max stack
usage rather than accessing internal RTX data directly. Wrap RTX5
specific code in OS_BACKEND_RTX5.

Also refactor the code to use mbed types rather than RTX types:
os_timer_t -> mbed_rtos_storage_timer_t
os_event_flags_t -> mbed_rtos_storage_event_flags_t
osRtxMutex_t -> mbed_rtos_storage_thread_t

RTOS: Thread: Update thread state docs

RTOS: Thread: Update docs; make singal_clr static as it's affects running thread

rtos Thread: Remove private copy constructor and assignment operators in favor of the NonCopyable traits.

Resolve Doxygen errors from RTOS. Fixed minor Doxygen bug in FileSystemHandle.h as well

Update codebase for CMSIS5/RTX5 ...

Update all of mbed-os to use RTX5.

rtos: Prevent Thread class from being copied ...

Make the copy constructor and assignment operator private to prevent
them from being used.

rtos: Add Inactive return to thread get state ...

If a thread hasn't been started return Inactive as the status when
Thread::get_state() is called.

rtos: Return an error when a Thread is re-used ...

Calling Thread::start multiple times leads to undefined behavior since
the Thread class was not designed to handle being restarted.  Return an
error code if Thread::start is called a second time to prevent this
behavior.

Renamed files in platform to match source names ...

critical.h     -> mbed_critical.h
sleep.h        -> mbed_sleep.h
toolchain.h    -> mbed_toolchain.h
rtc_time.h     -> mbed_rtc_time.h
semihost_api.h -> mbed_semihost_api.h
wait_api.h     -> mbed_wait_api.h

Remove Thread::wait from thread example

Remove invalid thread::start example ...

This changes reflects the correct syntax for spawning a thread that will execute a local function with given parameters.

Add tags to our code

For drivers, events, hal, platform, rtos and mbed.h add one level of path to make sure specific and unique includes files are found.

restructure - Restructured rtos directory