EXT-5480: Send viewer version info to Search server.

Added the following query parameters to the URL that is sent to the
search web server. This will allow them to do version-specific content
if necessary (such as using secondlife:///app/region for viewer's that
support it).

* channel = the viewer channel name, e.g. "Second Life Beta Viewer"
* version = the full version string, e.g. "2.0.0.2001234"
* major   = the viewer major version number, e.g., "2"
* minor   = the viewer major version number, e.g., "0"
* patch   = the viewer major version number, e.g., "0"
* build   = the viewer major version number, e.g., "2001234"