objdump reports correctly "byte" flag
Update "Hello, world!" example to demonstrate routine calls (CALL/RET)
SMP support, working boot system, code/data segments, mmap'ed areas

- CPUCores grouped in CPUs, CPUs grouped into Machine, IRQs and ports
  moved from CPU to Machine
- SMP now supported - multiple CPUs and cores, each with its own
  execution thread
- boot system finished, with proper initialization sequence
- code and data segments introduced
- service routines for CPUs - idle loop for IRQ/INT serving, ...
- memory supports mmap'ed areas - pages split into different types
  (anonymous, mmap) and file backend available, yet not accessible
  from setup nor code
- fixed INT/RETINT mechanism - nto all registers were pushed/popped
- assembler use 3 passes now, to allow yet-undefined references
- improved logging
Disable segments for now, need proper testing
Merge branch 'master' of github:happz/ducky