Implement native stack unwinding for Linux

Implement native stack unwinding for Linux
This change implements native stack unwinding using the libunwind on
Linux. I have also fixed bunch of issues / details in the related code:
1) 0x in front of %p inside format string
2) Subtraction of -1 from dl_info.dli_sname
3) Added .cfi_xxxx annotation to the CallDescrWorkerInternal and the
LEAF_ENTRY / LEAF_END macros.
4) Changed local labels in the CallDescrWorkerInternal to be prefixed by
.L to see the CallDescrWorkerInternal in the stack trace
5) Changed moveOWord to use movdqu - it was being called with one of the
parameters unaligned