Sync with Alchemy, includes much awaited lib updates for Linux

Applies ALCH-420 - Replace all invisiprims with fully transparent texture and remove dead code paths
-ARC no longer takes invisis into consideration.

Syncs some script keywords updates.

Changes all "\n" in llfloaterabout.cpp to '\n' because screw.dat

indra/llwindow/llwindowsdl.h

@@ -135,8 +135,6 @@ public:
 	Window mSDL_XWindowID;
 	Display *mSDL_Display;
 #endif
-	void (*Lock_Display)(void);
-	void (*Unlock_Display)(void);
 
 #if LL_GTK
 	// Lazily initialize and check the runtime GTK version for goodness.
@@ -216,6 +214,7 @@ private:
 	U32 mKeyScanCode;
         U32 mKeyVirtualKey;
 	SDLMod mKeyModifiers;
+	U32 mKeySym;
 };