Add "topology" term.

This term is introduced in the Server Discovery And Monitoring Spec and will be used in the Server Selection Spec as well.

Signed-off-by: Sam Kleinman <samk@10gen.com>
minor: whitespace cleanup
DOCS-2225: Mention size limit of reduce

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-4048: fixing weird linking effects
DOCS-4048: fixes to broken links in PDF
DOCS-4066: edit
DOCS-2539: Document ISODate JSON parsing restrictions.

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-2955 - added missing supported drivers, harmonized language, fixed typos

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-2076: Clarify references to using single config servers
DOCS-3995: Explain how sparse indexes interact with null queries.