setjmp is not guaranteed to collect all registers without modification
on all platforms.
This fixes the following bug: when the pointer of a newly allocated
object on the Python heap is stored in rpb registers on x86_64 arch, it
was not collected by the garbarge collector.
A script can now be imported in the console.
Moved all the MicroPython functions to python/port files.
Change-Id: I0a23e8cb20005719b800e81470e1c574c702c3b7
