This change set introduces the notions of registering compilation actions and code block actions into the diagnostics API. Compilation actions differ from compilation end actions in that they do not have access to per-compilation analyzer state and do not introduce action execution ordering constraints. Code block actions differ from code block end actions in that they do not have access to per-block analyzer state and do not introduce action execution ordering constraints.

This change set also removes RegisterXEndAction methods on contexts other than the corresponding StartXAnalysisContext types. This change is intended to guide analyzer authors towards introducing analyzer state with appropriate lifetime.

Some internal mechanism for the removed registration methods remains. This keeps the mechanism fully general and imposes a very marginal execution cost.

The specific API changes:
 -- Removal of AnalysisContext.RegisterCompilationEndAction. CompilationStartAnalysisContext.RegisterCompilationEndAction remains.
 -- Removal of AnalysisContext.RegisterCodeBlockEndAction and CompilationStartAnalysisContext.RegisterCodeBlockEndAction. CodeBlockStartAnalysisContext.RegisterCodeBlockEndAction remains.
 -- Introduction of AnalysisContext.RegisterCompilationAction.
 -- Introduction of AnalysisContext.RegisterCodeBlockAction and CompilationStartAnalysisContext.RegisterCodeBlockAction.
 -- Renaming of CompilationEndAnalysisContext to CompilationAnalysisContext.
 -- Renaming of CodeBlockEndAnalysisContext to CodeBlockAnalysisContext.

moved v1 engine to its own namespace and updated sources accordingly.

also added BaseDiagnosticIncrementalAnalyzer which contains all methods that engine needs to implement to make all other services which consume IDiagnosticAnalyzerService to just work.

probably later we will change it but for now, this should let us test v2 engine isolated without too much changes in other part of code base

     Background:

     As discussed in the dev team all hands all code under the GitHub dotnet foundation is using a single process for contribution, API review, infrastructure and coding style. The idea is to present a unified view to our customer and give them a single story for contributing to any project under the dotnet foundation.

     https://github.com/dotnet/corefx/wiki/Contributing#c-coding-style

     The coding style transition is automated using a Roslyn based rewrite tool:

     https://github.com/dotnet/codeformatter

     This will be applied in stages across our developer tree. Right now the focus is on the Open directory as this is what is being presented on github. Code owners will be contacted before the transition happens.

     Note: this is a soft style requirement. There are no build errors that come from this change.
 (changeset 1408227)