[externals] Add nrefactory as a submodule

Import NRefactory as a regular git submodule as compared to a source code
import. This makes updating and modifying it easier.
Bump to latest nrefactory
Merge branch 'master' into nrefactory_submodule

Conflicts:
	main/contrib/ICSharpCode.NRefactory.CSharp/Analysis/DefiniteAssignmentAnalysis.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Ast/AstNode.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Ast/DepthFirstAstVisitor.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Ast/Expressions/ArrayInitializerExpression.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Ast/GeneralScope/NamespaceDeclaration.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Ast/IAstVisitor.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Ast/ObservableAstVisitor.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Ast/SyntaxTree.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/CSharpProjectContent.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Completion/CSharpCompletionEngine.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Completion/CSharpCompletionEngineBase.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Completion/CSharpParameterCompletionEngine.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Completion/CompletionDataWrapper.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Completion/ICompletionContextProvider.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Formatter/AstFormattingVisitor.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Formatter/GeneratedCodeSettings.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj
	main/contrib/ICSharpCode.NRefactory.CSharp/OutputVisitor/CSharpOutputVisitor.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/OutputVisitor/CodeDomConvertVisitor.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Parser/CSharpParser.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Parser/mcs/cs-tokenizer.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Parser/mcs/driver.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Parser/mcs/support.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Refactoring/BaseRefactoringContext.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Refactoring/CodeActions/CreateBackingStoreAction.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Refactoring/CodeActions/GeneratePropertyAction.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Refactoring/CodeActions/InlineLocalVariableAction.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Refactoring/DocumentScript.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Refactoring/ICodeIssueProvider.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Refactoring/TypeSystemAstBuilder.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/CSharpAstResolver.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/CSharpConversions.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/CSharpInvocationResolveResult.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/CSharpResolver.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/DetectSkippableNodesNavigator.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/DynamicInvocationResolveResult.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/FindReferences.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/Log.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/OverloadResolution.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/OverloadResolutionErrors.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/ResolveAtLocation.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/Resolver/ResolveVisitor.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/TypeSystem/CSharpAssembly.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/TypeSystem/CSharpUnresolvedFile.cs
	main/contrib/ICSharpCode.NRefactory.CSharp/TypeSystem/TypeSystemConvertVisitor.cs
	main/contrib/ICSharpCode.NRefactory/Editor/ITextSource.cs
	main/contrib/ICSharpCode.NRefactory/Editor/ReadOnlyDocument.cs
	main/contrib/ICSharpCode.NRefactory/Editor/StringBuilderDocument.cs
	main/contrib/ICSharpCode.NRefactory/Editor/StringTextSource.cs
	main/contrib/ICSharpCode.NRefactory/IAnnotatable.cs
	main/contrib/ICSharpCode.NRefactory/ICSharpCode.NRefactory.csproj
	main/contrib/ICSharpCode.NRefactory/TypeSystem/CecilLoader.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/DefaultSolutionSnapshot.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/ExtensionMethods.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/IAttribute.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/IEntity.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/IFreezable.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/IInterningProvider.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/IProjectContent.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/ISolutionSnapshot.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/ISupportsInterning.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/IType.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/ITypeDefinition.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/ITypeReference.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/IUnresolvedFile.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/IVariable.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractFreezable.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractResolvedMember.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractUnresolvedEntity.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultAssemblyReference.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultResolvedTypeDefinition.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultUnresolvedEvent.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultUnresolvedField.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultUnresolvedMethod.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultUnresolvedProperty.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultUnresolvedTypeDefinition.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/MinimalCorlib.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/SimpleCompilation.cs
	main/contrib/ICSharpCode.NRefactory/TypeSystem/ParameterizedType.cs
	main/contrib/ICSharpCode.NRefactory/Utils/LazyInit.cs
	main/external/Mono.Cecil
[build] Nuke the last of the old nrefactory code