put a proper README.md at the top of the tree

README.md

-Convert old style llinfos and llwarns to new format
+Second Life Viewer
\ No newline at end of file
+==================
+
+This project manages the source code for the
+[Second Life](https://www.secondlife.com) Viewer.
+
+This source is available as open source; for details on licensing, see
+[https://wiki.secondlife.com/wiki/Linden_Lab_Official:Second_Life_Viewer_Licensing_Program](the
+licensing page on the Second Life wiki)
+
+For information on how to use and contribute to this, see
+[https://wiki.secondlife.com/wiki/Open_Source_Portal](the open source
+portal on the wiki).