Scripts/DB_Scripts: massive cleanup of SCRIPT_COMMAND_* related staff

* add union into ScriptInfo structure (thanks NoFantasy for the idea);
* move scripts methods from Map.cpp to new file MapScripts.cpp;
* remove magic numbers and introduce eScriptFlags enumeration.

It's just a beginning and more changes to come. Stay tuned!

--HG--
branch : trunk

src/server/game/Maps/Map.h

@@ -53,6 +53,14 @@ class Battleground;
 class MapInstanced;
 class InstanceMap;
 
+struct ScriptAction
+{
+    uint64 sourceGUID;
+    uint64 targetGUID;
+    uint64 ownerGUID;                                       // owner of source if source is item
+    ScriptInfo const* script;                               // pointer to static script data
+};
+
 //******************************************
 // Map file format defines
 //******************************************