- use IRQStack for ISRs (at begening of SRAM) (let's call it the irq stack)
- use end of heap for stack needed during initialization (let's call it the init stack).
- the systemStats in GCS indicate the remaining bytes in the IRQ stack (this is realy usefull to monitor our (nested) IRQs.
This is the base ground to provide as much memory as possible available at task creation time.
Next step is to re-organize the initialization in order to move all the init out of the thread's stacks onto the init stack.
This will provide as much memory as possible available at task creation time.
Basically the stack during initialization will be destroyed once the scheduler starts and dynamic alloc are made (since the init stack is at the end of the heap). We will need to make sure we don't clobber the heap during initialization otherwise this will lead to stack corruption.
- only affect flight/PiOS (no change for posix and win32)
- tested on recent master (some runtime on CC with GCS)
- the new timer feature is not compiled-in since we don't use it yet.
- NO TEST FLIGHT
