reorg of indexing strategies

Signed-off-by: Sam Kleinman <samk@10gen.com>
minor: restructure index applications documents and TOC
reorg of geospatial docs

Signed-off-by: Sam Kleinman <samk@10gen.com>
adding geo redirects
reorg of gridfs

Signed-off-by: Sam Kleinman <samk@10gen.com>