[ADD] Locking revised; now based on visitor
[MIN] lock2 -> lock
[FIX] GUI, Server Dialog: "Access denied". Closes #684
[FIX] XQuery: only allow values to be bound to queries (no expressions)
Merge branch 'visitor-locking'
[Core, Locking]: Refactoring for supporting RestXQ
[MOD] XQuery, Visitor Locking: merge, various fixes
Merge pull request #687 from JensErat/visitor-locking

[Core, Locking]: Refactoring for supporting RestXQ
Merge branch 'master' into visitor-locking
[MOD] RESTXQ: database locking support
[FIX] XQuery, resource management (#685): check case on Linux systems
[FIX] XQuery, reallow Expr bindings (required by QT3TS)
[FIX] Commands, XML Syntax: whitespace check revised
[MOD] XQuery, parser: performance tweaks
[MOD] XQuery, performance tweaks (XQParser.xq)
[MOD] XQuery, performance tweaks (XQParser.xq)
[MIN] XQuery, UserFuncs: function caching rewritings
[FIX] XQuery, QT3TS: disallow serialization of attributes and ns. (sigh)
[FIX] XQuery, QT3TS: Serialization tests
[FIX] XQuery: disallow call of private function in other static context