Initial round 2 memory allocation changes. THIS IS A WORK IN PROGRESS.

Initial round 2 memory allocation changes.  THIS IS A WORK IN PROGRESS.
includes single to multiple hooks changes.
ber_mem* reimplementation.
namespace glue (finally naming has not be decided upon nor implemented).
Added ldap_int_strdup to handle "internal" strdup'ing, this version uses hooks.
ldap_pvt_strdup still available for when strdup() is missing, this version
directly uses system allocators.
Updated -lldif to use ber allocators.  Items returned by ldif routines
should be ber_memfree()d as needed.