Adds support to m_highlightJSON in RuleMessage class

This variable helds a JSON with information regarding all matches.
Only filled when IncludeFullHighlightLog property is set.

headers/modsecurity/modsecurity.h

@@ -262,7 +262,7 @@ extern "C" {
      * Notice that the highlight can be calculate post-analisys. Calculate it
      * during the analisys may delay the analisys process.
      *
-    */
+     */
      IncludeFullHighlightLogProperty = 4,
     };
 

headers/modsecurity/rule_message.h

@@ -151,6 +151,7 @@ class RuleMessage {
 
     std::list<std::string> m_tags;
     RuleMessageHighlight m_highlight;
+    std::string m_highlightJSON;
 };