Define wxDEBUG_LEVEL in both debug and release builds as 1.

By default include assertions and debug logging in both debug and release
builds but disable them in application release builds (when NDEBUG is
defined).

Also update (more accurately, replace) debugging overview.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61886 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/log.h

@@ -1396,3 +1396,24 @@ void wxLogSysError(const char* formatString, ... );
 void wxVLogSysError(const char* formatString, va_list argPtr);
 //@}
 
+/** @addtogroup group_funcmacro_debug */
+//@{
+
+/**
+    @def wxDISABLE_DEBUG_LOGGING_IN_RELEASE_BUILD()
+
+    Use this macro to disable logging at debug and trace levels in release
+    build when not using IMPLEMENT_APP().
+
+    @see wxDISABLE_DEBUG_SUPPORT(),
+         wxDISABLE_ASSERTS_IN_RELEASE_BUILD(),
+         @ref overview_debugging
+
+    @since 2.9.1
+
+    @header{wx/log.h}
+ */
+#define wxDISABLE_DEBUG_LOGGING_IN_RELEASE_BUILD()
+
+//@}
+