new method: ResetGFX();

exposes the GFX->beginReset(); method to script to allow folks to force the gbuffer to reinitialize (if, say a custom element is holding on to data in a buffer and it needs a cleaning, to name one example)

Engine/source/gfx/gfxDevice.cpp

@@ -1329,3 +1329,8 @@ DefineEngineFunction( getBestHDRFormat, GFXFormat, (),,
 
    return format;
 }
+
+DefineConsoleFunction(ResetGFX, void, (), , "")
+{
+   GFX->beginReset();
+}