Left some TODOs in FirebirdInterface.idl and utilities/ntrace/TracePluginImpl.cpp related to trace.
(redo with fix for Windows build, and left another TODO comment in FirebirdInterface.idl)
Also some cleanups, the most important are:
- meaningful ctor on Jrd::Lock, helping to avoid code dup
- avoid unneeded h-file dependencies, making boot build engine dependent