misc other cleanup

(slapi_x_XXX is still reserved for exported functions that are not part
of the SLAPI specification)

case in extended_op

(please review)

consolidated into the Operation structure. All reply parameters
are consolidated into the new SlapReply structure. Most operations
now have identical call signatures... Changes are not #ifdef'd,
revert to -r NO_SLAP_OP_BLOCKS if necessary to back out.

from jenarusa@us.ibm.com

for the known exops.

rename "no referrals" controls to "domain scope"
misc cleanup

using LDAP_DEVEL (to indicate experimental) to enable experimental features
(true for HEAD unless LDAP_REL_ENG is defined)

failure

Rename internal slapi_XXX API to slapi_x_XXX
Always set result code/matched/error text in operation parameter block
to make available to postoperation plugins

Connection, Operation and Backend structures.

Ensure that SLAPI_MODIFY_MODS is set to an array of LDAPMods.

SLAPI - Netscape plugin API for slapd - based on patch contributed by Steve Omrani <somrani@us.ibm.com> as ITS#2073

Coverted LDAP_LOG macro to use subsystem ID int values instead of string values