- Support specifying URL in loginParameters for connecting to OpenSim

- Patch some miscellaneous OpenSim related glitches
- Add waitForRegionHandshake function
- Add a concurrent promise queue
- Fix xml writing of Vector3s
- Fix asset downloading on grids without HTTP assets
- Fix buildObject to properly orientate prims
- Wrangled with CreateSelected all day and it turned out to be an OpenSim bug
- LinkFrom function for faster linking
- Updated LLSD library to fix LLMesh decoding

example/loginParameters.example.json

@@ -2,5 +2,6 @@
   "firstName": "Username",
   "lastName": "Resident",
   "password": "YourPassword",
-  "start": "last" //first, last, or login uri like uri:<existing region name>&<x>&<y>&<z>
-}
+  "start": "last", //first, last, or login uri like uri:<existing region name>&<x>&<y>&<z>
+  "url": "https://login.agni.lindenlab.com/cgi-bin/login.cgi"
+}