Removed Old Generate Code artifacts from project
Simplified getting all mixins for a target file
Initialize MixinGenerationPlan when creating CodeGenerationPlan
Wire up ImplementationDetails.ParentMemberWrapper
Consume the new CodeBehindSyntaxTree
Pull in the correct CodeGenrationPlan
Initialize the MixinGenerationPlans when creating the CodeGenerationPlan
Removed old GenerateCode artifacts
Whitespace
Remove Source Code property from CodeGeneratorProxy.  And added flag to conditionally add the Code Generated attribute
Create External Mixin Specific Auto Generated Namespace
Whitespace
CreateAbstractMembersWrapperTypeDeclaration
Fixed copy/paste bug
Fixed logic bug
Documentation
Convert readonly to const
Implementation for IMixinRequiremens and ISharedRequirements
Added null check
Simplified code