v1.2.0: Introducing Self-Managed stack memory

• INTRODUCING Self managed stack, now it is possible to have self-managed stack memory for any threads, no need to define stack size... (although use it with care) just by no providing a stack memory, AtomicX will automatically switch the tread to self-managed, to do just use atomicx() default constructor instead.

  Notes:
  * It will only entries the stack enough to hold what is needed if the used stack is greater than the stack memory managed.
  * No decrease of the stack size was added to this release.
  * In case your thread is not able to resize the stack, if it needs more, StackOverflowHandle is called.

Examples:
- Ardunino/Simple
- avrAutoRobotController

• Explicitly added the pc example shown here to to examples/pc as simple along with makefile for it.
  Also updated it to have an example of Self-managed stack memory as well.