Fixes NPE
Remove Unnecessary Usings
Merge pull request #430 from SlavaRa/fixes-TraceManager

Fixes Null References Error from TraceManager.Add(null);
Fixes Null References Error from 'new FileModel(null)'
Merge pull request #431 from SlavaRa/fixes-ASCompletion.Model.FileModel

Fixes Null References Error from 'new FileModel(null)'
Fixes Null References Error from ASCompletion.Context.ASContext->GetDeclarationAtLine() if ASCompletion.Context.ASContext->cFile == null
Merge pull request #432 from SlavaRa/fixes-ASCompletion.Context.ASContext

Fixes Null References Error from ASCompletion.Context.ASContext->GetDeclarationAtLine()