[FIX] initialize IdPreMap if UPDINDEX is true
Merge pull request #665 from LeoWoerteler/gh-663

[FIX] Avoid infinite recursion in StaticUserFunc#databases(..).
[MOD] XQuery: more compact notation of error messages
[MOD] XQuery, format-date/time: parsing code revised
[FIX] GH-658: Evaluate XQUnit tests in the correct scope.
[MOD] Static functions aren't expressions.