API BREAKER: Replacing defines in irrTypes.h which are conflicting with c++ reserved identifier rules.

C++ has undefined behavior for identifiers starting with __ or with _ followed by an uppercase letter.
We still have many more (in IrrCompileConfig.h and in all header-guards), will likely replace those later as well.
As a workaround for users which might use irrlicht defines in their code, I've added the header irrLegacyDefines.h
Including that allows to continue using old defines for a while - or make it easier to have code which compiles 
with old and new Irrlicht library versions.


git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6251 dfc29bdd-3216-0410-991c-e03cc46cb475

source/Irrlicht/ISceneNodeAnimatorFinishing.h

@@ -20,7 +20,7 @@ namespace scene
 		ISceneNodeAnimatorFinishing(u32 finishTime)
 			: FinishTime(finishTime), HasFinished(false) { }
 
-		virtual bool hasFinished(void) const _IRR_OVERRIDE_ { return HasFinished; }
+		virtual bool hasFinished(void) const IRR_OVERRIDE { return HasFinished; }
 
 	protected:
 
@@ -33,4 +33,3 @@ namespace scene
 } // end namespace irr
 
 #endif
-