Simplified TestsSimpleModuleResolver.
Refactor TestsSimpleModuleResolver to use AbstractSemanticContext.
Tests for package namespace.
Refactor Reference node to use semantics class.
Made Expressions use semantics class.
Minor method cleanup
Refactored CommonDefUnitSearch into Lang ScopeLookup.
Added CompletionScopeLookup to Lang-Engine.
Moved Lang-Engine classes to own src-folder.
ElementDoc into Lang-Engine