non-root add/delete of entries rooted at '' checks children write permission (forward port from back-ldbm)

timelimit must be checked on first entry.

trival other cleanup.

unbind call around free of sasl data.

Patch provided by John Morrissey <jwm@horde.net>

Use pres indices to support LE/GE [<=,>=] filters.

must be set later using dbenv_set_flags.

the patch from ITS#1289 to be ported here.