Moving headers used by both server and client to special folder
These are the header files which are used by both client and server:
This patch is about moving these header files to special folder
(src/shared). It will be easier to identify these headers when looking
for them in the src tree.
util_safalign.h is renamed as safalign.h because util_ namespace is
appropriate when this file belonged to the util's folder which is no
longer the case.
Reviewed-by: Fabiano Fidêncio <firstname.lastname@example.org>