Allow turning flying on and off while seated, if using Continue Fly On Unsit

Note: Redundant code, but these functions will likely be merged eventually(FUI-esque project), so it doesn't matter for now.

indra/newview/llagent.cpp

@@ -666,11 +666,13 @@ void LLAgent::setFlying(BOOL fly)
 			return;
 		}
 
+		/* Singu Note: We don't take off while sitting, don't bother with this check, let us toggle fly whenever.
 		// don't allow taking off while sitting
 		if (fly && gAgentAvatarp->isSitting())
 		{
 			return;
 		}
+		*/
 	}
 
 	if (fly)

indra/newview/lltoolbar.cpp

@@ -307,7 +307,12 @@ void LLToolBar::refresh()
 	setVisible(show && !mouselook);
 
 	BOOL sitting = FALSE;
-	if (gAgentAvatarp)
+	static LLCachedControl<bool> continue_flying_on_unsit("LiruContinueFlyingOnUnsit");
+	if (continue_flying_on_unsit)
+	{
+		sitting = false;
+	}
+	else if (gAgentAvatarp)
 	{
 		sitting = gAgentAvatarp->isSitting();
 	}

indra/newview/llviewermenu.cpp

@@ -3984,7 +3984,12 @@ class LLWorldEnableFly : public view_listener_t
 	bool handleEvent(LLPointer<LLEvent> event, const LLSD& userdata)
 	{
 		BOOL sitting = FALSE;
-		if (gAgentAvatarp)
+		static LLCachedControl<bool> continue_flying_on_unsit("LiruContinueFlyingOnUnsit");
+		if (continue_flying_on_unsit)
+		{
+			sitting = false;
+		}
+		else if (gAgentAvatarp)
 		{
 			sitting = gAgentAvatarp->isSitting();
 		}