Nested classes support is diversified, depending on the language capability. If the language cannot support nested classes, they will be unconditionally moved to the global namespace. If language module does not override Language::nestedClassesSupport() function, nested classes will be ignored, unless "feature:flatnested" is used.
filtered warnings, turned on "flatnested" for nested template test
added forward declaration instead of ignored nested class (resurrected old code)
%feature ("flatnested") is set for nested scope test
warnfilter fixed
scoping for "anonymous forward declaration" fixed
more warnings removed
WARN_PARSE_UNNAMED_NESTED_CLASS check fixed
error order foxed
warning filter fixed
nested nested class warning filtered
warnings suppressed for deeply nested classes
Typo in comment fix
Restore warning suppression in testcase
Merge branch 'wkalinin-nested-ignore'

* wkalinin-nested-ignore:
  Restore warning suppression in testcase
  Typo in comment fix
  warnings suppressed for deeply nested classes
  nested nested class warning filtered
  warning filter fixed
  error order foxed
  WARN_PARSE_UNNAMED_NESTED_CLASS check fixed
  more warnings removed
  warnfilter fixed scoping for "anonymous forward declaration" fixed
  %feature ("flatnested") is set for nested scope test
  added forward declaration instead of ignored nested class (resurrected old code)
  filtered warnings, turned on "flatnested" for nested template test
  Nested classes support is diversified, depending on the language capability. If the language cannot support nested classes, they will be unconditionally moved to the global namespace. If language module does not override Language::nestedClassesSupport() function, nested classes will be ignored, unless "feature:flatnested" is used.