Import experimental referral implementation from OPENLDAP_DEVEL_REFERRALS.
Includes support for update referral for each replicated backend. Reworked replication test to use update referral. Includes major rewrite of response encoding codes (result.c). Includes reworked alias support and eliminates old suffix alias codes (can be emulated using named alias). Includes (untested) support for the Manage DSA IT control. Works in LDAPv2 world. Still testing in LDAPv3 world. Added default referral (test009) test.