Merge remote-tracking branch 'origin/topic/timw/266-namespaces'

Merge adjustments:

- Preserved original `base_type_no_ref` argument type as ::TypeTag
- Removed superfluous #pragma guard around deprecated TableVal ctor
- Clarify NEWS regarding MetaHook{Pre,Post} deprecations
- Simplify some `::zeek::` qualifications to just `zeek::`
- Prefixed FORWARD_DECLARE_NAMESPACED macro with ZEEK_

* origin/topic/timw/266-namespaces:
  Disable some deprecation diagnostics for GCC
  Rename BroType to Type
  Update NEWS
  Review cleanup
  Move Type types to zeek namespace
  Move Flare/Pipe from the bro namespace to zeek::detail
  Move Attr to the zeek::detail namespace
  Move Trigger into the zeek::detail namespace
  Move ID to the zeek::detail namespace
  Move Anon.h into zeek::detail namespace
  Mark all of the aliased classes in plugin/Plugin.h deprecated, and fix all of the plugins that were using them
  Move all of the base plugin classes into the zeek::plugin namespace
  Expr: move all classes into zeek::detail
  Stmt: move Stmt classes into zeek::detail namespace
  Add utility macro for creating namespaced aliases for classes

src/RuleCondition.h

@@ -2,11 +2,13 @@
 
 #include <stdint.h> // for u_char
 #include <sys/types.h> // for u_char
+#include "util.h"
 
-class ID;
 class Rule;
 class RuleEndpointState;
 
+ZEEK_FORWARD_DECLARE_NAMESPACED(ID, zeek::detail);
+
 // Base class for all rule conditions except patterns and "header".
 class RuleCondition {
 public:
@@ -111,7 +113,5 @@ public:
 
 	void PrintDebug() override;
 private:
-	ID* id;
+	zeek::detail::ID* id;
 };
-
-