Add Default Avatar Picker Floater (World->Default Avatars)

Default Avatars button option added to Toolbar prefs.
Adds debug setting ToolbarVisibleAvatar
Hooks into "avatar_picker_url" login response on opensim.
Also includes hooking up of DestinationGuideShown to startup, which was left unstaged from the initial commit of the Destination Guide.

indra/newview/llfloateravatar.cpp

@@ -0,0 +1,65 @@
+/** 
+ * @file llfloateravatar.h
+ * @author Leyla Farazha
+ * @brief floater for the avatar changer
+ *
+ * $LicenseInfo:firstyear=2011&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2011, Linden Research, Inc.
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * 
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+/**
+ * Floater that appears when buying an object, giving a preview
+ * of its contents and their permissions.
+ */
+
+#include "llviewerprecompiledheaders.h"
+
+#include "llfloateravatar.h"
+#include "llmediactrl.h"
+#include "lluictrlfactory.h"
+#include "llweb.h"
+
+
+LLFloaterAvatar::LLFloaterAvatar(const LLSD& key)
+	:	LLFloater(key)
+{
+	LLUICtrlFactory::getInstance()->buildFloater(this, "floater_avatar.xml", NULL, false);
+}
+
+LLFloaterAvatar::~LLFloaterAvatar()
+{
+}
+
+BOOL LLFloaterAvatar::postBuild()
+{
+	enableResizeCtrls(true, true, false);
+	LLMediaCtrl* avatar_picker = findChild<LLMediaCtrl>("avatar_picker_contents");
+	if (avatar_picker)
+	{
+		avatar_picker->setErrorPageURL(gSavedSettings.getString("GenericErrorPageURL"));
+		std::string url = gSavedSettings.getString("AvatarPickerURL");
+		url = LLWeb::expandURLSubstitutions(url, LLSD());
+		avatar_picker->navigateTo(url, "text/html");
+	}
+	return TRUE;
+}
+
+