Update to three.js r61

Copied from https://github.com/virtual-world-framework/three.js.git
Revision 8471bc8564fc2bf8b3360460bf20db0c630168df

Refs #2865
Merge pull request #45 from virtual-world-framework/branch/threejs-61

Branch/threejs 61
Remove command-center-threejs per #2467

/cc @bcbarsness
Merge pull request #46 from virtual-world-framework/branch/remove-threejs-command-center

Remove threejs command center
Add handler to node.js server for vwf /admin/chrome requests

fixes #2891
Have HandleAdminChrome return an empty string if html overlay does not exist

refs #2891
Merge pull request #48 from virtual-world-framework/branch/node.js-chrome-requests

Branch/node.js chrome requests
Pull out repeated code into a parseSocketUrl function

fixes #2893
Merge branch 'development' into branch/editor-optimization