Cleanup of LoggingService and updated deprecation message in extension schemas.

...base/ui/dialog/ModelElementWithRefCopyMessageHandler.java

...rtiss.tooling.kernel/trunk/schema/constraintVerifier.exsd

...ortiss.tooling.kernel/trunk/schema/logMessageHandler.exsd

...ortiss.tooling.kernel/trunk/schema/migrationProvider.exsd

...ooling.kernel/trunk/schema/modelConnectionCompositor.exsd

...s.tooling.kernel/trunk/schema/modelElementCompositor.exsd

...ng.kernel/trunk/schema/modelElementConstraintChecker.exsd

...oling.kernel/trunk/schema/modelElementLibraryHandler.exsd

...s.tooling.kernel/trunk/schema/modelPrototypeProvider.exsd

...iss.tooling.kernel/trunk/schema/modelStorageProvider.exsd

...s.tooling.kernel/trunk/schema/transformationProvider.exsd

...l/trunk/src/org/fortiss/tooling/kernel/ToolingKernel.java

...g/fortiss/tooling/kernel/extension/LogMessageHandler.java

...org/fortiss/tooling/kernel/extension/data/LogMessage.java

...ooling/kernel/extension/data/LogMessageWithException.java

...c/org/fortiss/tooling/kernel/internal/LoggingService.java

...ortiss/tooling/kernel/internal/ToolingKernelInternal.java

...c/org/fortiss/tooling/kernel/service/ILoggingService.java