Sync with Upstream Alchemy

Changes LLEnvManagerNew::setRegionChangeCallback to LLAgent::addRegionChangedCallback
Cleans up some of the timeout policies that aren't necessary any longer.
Modernizes parts of LLViewerKeyboard, updates llregistry.h
Begins changeover from LLDynamicArray to std::vector
Minor merge of newer, trivial SSA functions.
Introduces LLAgent functions: addParcelChangedCallback and canJoinGroups
Support for secondlife:///app/appearance SLapps.
Cleans up older functions.

indra/newview/app_settings/settings_ascent.xml

@@ -124,6 +124,17 @@
       <key>Value</key>
       <integer>0</integer>
     </map>
+    <key>AlchemyRainbowEffects</key>
+    <map>
+      <key>Comment</key>
+      <string>Makes agent effects rainbows!</string>
+      <key>Persist</key>
+      <integer>1</integer>
+      <key>Type</key>
+      <string>Boolean</string>
+      <key>Value</key>
+      <integer>0</integer>
+    </map>
     <key>AlchemyRegionRestartShake</key>
     <map>
       <key>Comment</key>