Modify slapd syntax struct to have both a validation and normalization

routine.  Could be combined into one routine.
Modify slapd matching rule struct to only have match function.
Modify old attribute such that 'bin' implies octetString, not 'binary'.
Add compatibility for IA5 strings.  Only directoryStrings were handled
before.
Treat attribute types without syntax as incomplete, not default.
Add OctetStringValidate (always returns okay).
Add {UTF8,IA5}StringValidate/Normalize  (IA5 based loosely on
case_exact_normalize).  Need case{Exact,Ignore}UTFMatch, using IA5 versions
for now.
Removed default of syntax/mr handlders, should just skip
registration of syntax/mr's without handlers.
Added comments to slap.h about types versus descriptions.