graying unused declarations
SourceCodeClassifier peeks meaningful categories, then Other, then Unused if there are many for one symbol

fix the order in which SourceCodeClassifier peeks categories

fix compilation
ResolveUnopenedNamespace tagger skeleton
add ResolveUnopenedNamespaceSmartTaggerProvider
add LanguageService.GetAllEntitiesInProjectAndReferencedAssemblies
show top 5 entities as actions in ResolveUnopenedNamespaceTagger
ResolveUnopenedNamespaceTagger shows real type suggestions
fix compilation after rebase
ResolveUnopenedNamespaceTagger shows "open..." actions and full entities names. The latter works.
ResolveUnopenedNamespaceTagger traverses untyped AST to find a place where it should add open statement
everything seems to work
ResolveUnopenedNamespaceTagger uses partial current project signature and traverses nested entities
filter out irrelevant modules
respect current namespace / module
referenced assemblies checked again
fixed: open statement inserted in wrong place
extract entity refining logic into Entity.tryCreate
add Entity.tryCreate tests
fix compilation
move Ast.findNearestOpenStatementBlock to Core project