catch error in validation/pretty functions

	- memory based session history to minimize sync traffic
	- when client is covered by a session history, then
      [add+delete] mode is used
	- when client cookie is not covered by the history because
      the cookie is too outdated and/or the history is truncated,
	  [add+present] mode is used
2. Sync cookie syntax : comma separated name=value pairs
	- csn=yyyymmddhh:mm:ssZ#0xSSSS#r#ssssr,sid=nnn

  moved labeledURI into system schema
  attribute types that inherit from labeledURI may be used in dynamic
    groups e.g. access to * by group/groupOfURLs/memberURL=foo

Need to add specific routines for schema attribute types

re-add objectClass pretty routines

(be liberal in what you accept, strict in what you generate)

Make SLAP_NVALUES the default.

from IBM India Research (Apurva Kumar)
Code review by Pierangelo, Kurt, and Jong.