Add Destination Guide

Adds llfloaterdestinations.* and floater_destinations.xml (needs translations, but not really)
Adds GenericErrorPageURL, DestinationGuideURL (not persistent), DestinationGuideShown, and DestinationGuideRect to debug settings
Removes ShowcaseURLDefault in favor of DestinationGuideURL from upstream.
Also Adds ToolbarVisibleDestinations for the toolbar button, but I'll need to set up a nice way to make the button invisible when the url is empty before adding it to the gui... maybe.. or maybe it's just not important.

This commit comes with support for dynamically changing destination guide page based on opensimextras simulator features cap

indra/newview/app_settings/settings.xml

@@ -547,17 +547,6 @@
     <key>Value</key>
     <string />
   </map>
-  <key>ShowcaseURLDefault</key>
-  <map>
-    <key>Comment</key>
-    <string>URL to load for the Showcase tab in Second Life</string>
-    <key>Persist</key>
-    <integer>0</integer>
-    <key>Type</key>
-    <string>String</string>
-    <key>Value</key>
-    <string>http://secondlife.com/app/showcase/index.php?</string>
-  </map>
 
   <key>CheckForGridUpdates</key>
   <map>
@@ -6069,6 +6058,44 @@ This should be as low as possible, but too low may break functionality</string>
       <key>Value</key>
       <string>89556747-24cb-43ed-920b-47caed15465f</string>
     </map>
+    <key>DestinationGuideRect</key>
+    <map>
+      <key>Comment</key>
+      <string>Rectangle for destination guide</string>
+      <key>Persist</key>
+      <integer>1</integer>
+      <key>Type</key>
+      <string>Rect</string>
+      <key>Value</key>
+      <array>
+        <integer>0</integer>
+        <integer>0</integer>
+        <integer>0</integer>
+        <integer>0</integer>
+      </array>
+    </map>
+    <key>DestinationGuideShown</key>
+    <map>
+      <key>Comment</key>
+      <string>Show destination guide</string>
+      <key>Persist</key>
+      <integer>1</integer>
+      <key>Type</key>
+      <string>Boolean</string>
+      <key>Value</key>
+      <integer>0</integer>
+    </map>
+    <key>DestinationGuideURL</key>
+    <map>
+      <key>Comment</key>
+      <string>Destination guide contents</string>
+      <key>Persist</key>
+      <integer>0</integer>
+      <key>Type</key>
+      <string>String</string>
+      <key>Value</key>
+      <string>http://lecs-viewer-web-components.s3.amazonaws.com/v3.0/[GRID_LOWERCASE]/guide.html</string>
+    </map>
     <key>DisableCameraConstraints</key>
     <map>
       <key>Comment</key>
@@ -17887,6 +17914,17 @@ This should be as low as possible, but too low may break functionality</string>
       <key>Value</key>
       <integer>0</integer>
     </map>
+    <key>GenericErrorPageURL</key>
+    <map>
+      <key>Comment</key>
+      <string>URL to set as a property on LLMediaControl to navigate to if the a page completes with a 400-499 HTTP status code</string>
+      <key>Persist</key>
+      <integer>1</integer>
+      <key>Type</key>
+      <string>String</string>
+      <key>Value</key>
+      <string>http://common-flash-secondlife-com.s3.amazonaws.com/viewer/v2.6/agni/404.html</string>
+    </map>
     <key>WebProfileFloaterRect</key>
     <map>
       <key>Comment</key>